medicina interna 2

Ibuprofen—Blood 667

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Ibuprofen—BloodNorm.

SI UnitsTherapeutic level 10-50 µg/mL 49-243 µmol/LToxic level 100-700 µg/mL 485-3395 µmol/L

Overdose Symptoms and TreatmentNote: Treatment choice(s) depend(s) on client’s history and condition and episode history.Symptoms. The amount of ibuprofen ingested does not correlate well with symptoms. Ibuprofen overdose usually produces minimal symptoms of toxicity and is rarely fatal. Onset of symptoms generally occurs within 4 hours after ingestion, and clients with normal renal function usually recover completely within 24 hours with supportive care. Typical signs and symptoms include mild gastrointestinal symptoms such as nausea, anorexia, vomiting, and abdominal pain. Other signs and symptoms that may occur include gastrointestinal hemorrhage (especially in the elderly), headache, CNS depression (light-headedness, drowsiness, lethargy, coma), seizures, nystagmus, diplopia, tinnitus, hyperventilation, rash, hypotension, bradycardia, hypoprothrombinemia, hypo-thermia, hepatic failure, apnea, respiratory depression, and cardiac arrest. Renal insufficiency and secondary acute renal failure are generally reversible with supportive therapy.

Treatment of Overdose in Adults

Ingestion of <100 mg/kg Encourage intake of milk or water to decrease gastrointestinal toxicity.

Ingestion of >100 mg/kg Empty the stomach by emesis using ipecac syrup or gastric lavage. (Do NOT induce vomiting in clients with a decreased level of consciousness, clients with an absent or depressed gag reflex, or a client with a history of a seizure disorder.) After gastric emptying, a saline cathartic should be given.

Laboratory Monitoring Renal function studies (BUN, creatinine, urinalysis): baseline and repeated in 1-2 weeks, ABG, CBC, liver function studies

Management of Specific Symptoms

Hypotension IV fluids and dopamine if neededSeizures (recurrent) IV diazepam, followed by barbituratesSymptomatic Atropine for bradycardiaSevere metabolic May treat with sodium bicarbonate (acidosis, pH <7.10)Renal failure Dopamine, dobutamine

1. The effectiveness of urine alkalinization to enhance urinary excretion is controversial.2. Hemodialysis is not effective in the treatment of toxicity because of the high degree of

protein binding of the drug.

668 Ibuprofen—Blood

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3. Monitor for hematuria and proteinuria.4. Observe and assess vital signs and neurologic status of symptomatic adults for 24 hours.5. Asymptomatic adults should be observed for 4 hours.6. Safety considerations and psychiatric consultation are indicated in intentional overdose.

Treatment of Overdose in ChildrenAmount Ingested Treatment<100 mg/kg Generally unlikely to result in toxicity

Home observationCaregiver education regarding signs and symptoms to monitor for

any dangers of childhood poisoning100-200 mg/kg Empty the stomach by emesis and observe for 4 hours. (Do NOT

induce vomiting in clients with a decreased LOC or an absent or depressed gag reflex, a child who ingested >400 mg/kg, or a client with a history of a seizure disorder.)

200-400 mg/kg Gastric decontamination, followed by cathartic. Observe at least 4 hours.

>400 mg/kg Immediate gastric lavage. Observe child carefully for seizure activity.

Usage. Ibuprofen blood levels are not gen-erally indicated; however, they may be useful to identify drug concentrations when over-dose, misuse, toxicity is suspected. Monitor-ing therapeutic levels in long-term ibuprofen use or when high doses are used in children with cystic fibrosis.

Description. Ibuprofen is a nonsteroidal anti-inflammatory drug (NSAID) that is also used for its antipyretic and analgesic activity. Its anti-inflammatory action is believed to be attributable to the inhibition of the synthesis or release of prostaglandins and to its antipyretic effect because of its action on the hypothalamus, with heat dis-sipation increased as a result of vasodilata-tion and increased peripheral blood flow. Ibuprofen is rapidly absorbed from the gas-trointestinal tract and is 99% protein bound. It is metabolized in the liver and almost completely excreted in the urine 24 hours after ingestion. Half-life is 2-4 hours, with peak blood levels reached in 1-2 hours, though it may take up to 2 weeks to achieve therapeutic response for chronic inflamma-tory problems. Ibuprofen is used for rheumatoid arthritis and osteoarthritis, musculoskeletal disorders, fever, primary dysmenorrhea, gout, and dental pain. It can increase bleeding time by inhibiting platelet aggregation, though this action is reversible within 24 hours after the medication is dis-continued. High-performance liquid chro-matography is used to establish ibuprofen blood levels.

Professional ConsiderationsConsent form NOT required.

Preparation1. Tube: Red topped. Plasma may be accept-

able from tubes with heparin (green topped), EDTA (lavender topped), or sodium fluoride/potassium oxalate (gray topped). Use of gel tubes (red/gray topped) is NOT advised.

Procedure1. Draw blood from opposite arm if client is

receiving ibuprofen intravenously. Draw a 3-mL blood sample.

2. Refrigerated samples can be used for up to 2 weeks.

Postprocedure Care1. If toxic levels are found, withhold the

drug and notify the physician.

Client and Family Teaching1. If overdose is suspected, prepare the client

and family for supportive treatment out-lined previously.

2. If overdose or toxicity occurred in child, instruct the child’s parents or caregiver in safe, accurate administration of ibupro-fen and review safety issues regarding prevention of accidental poisoning.

3. Refer clients with intentional overdose for crisis intervention.

Factors That Affect Results1. None found.

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IgM 669

Other Data1. “STAT” ibuprofen blood levels are not

widely available and are not frequently used in overdose or suspected toxicity cases. Because blood levels are not readily available during the relevant initial 4-hour period and there is little correla-tion between ibuprofen blood levels and symptoms, the management of ibu-profen overdose focuses on symptom management.

2. Ibuprofen blood levels are not generally monitored during routine ibuprofen therapy. Therapeutic response is moni-tored by evaluation of the degree of symptom relief.

3. Ibuprofen may decrease renal function because of the inhibition of renal prosta-glandin synthesis. This is especially important in clients with decreased renal function or congestive heart failure, because renal prostaglandins may have a role in supporting renal perfusion in these clients. Serum BUN and creatinine levels should also be monitored in clients with impaired renal function, heart failure, or hepatic dysfunction, those receiving nephrotoxic drug concomi-tantly, dehydrated clients, and geriatric clients.

4. Liver-function studies should be moni-tored in long-term ibuprofen therapy.

IFN Gamma AssaySee RD1-Interferon Tests for Tuberculosis—Blood.

iFOBTSee Immunochemical Fecal Occult Blood Testing—Stool

IgASee Immunoglobulin A—Serum.

IgDSee Immunoglobulin D—Serum.

IgESee Immunoglobulin E—Serum.

IgGSee Immunoglobulin G—Serum.

IgMSee Immunoglobulin M—Serum.

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670 125I-Labeled Fibrinogen (Fibrinogen Uptake) Leg Scan—Diagnostic

125I-Labeled Fibrinogen (Fibrinogen Uptake) Leg Scan—Diagnostic4. Assess for swelling in the calf, tenderness,

and cyanosis of the skin.5. Assess for Homans’ sign. Once it is deter-

mined to be positive, do NOT repeat Homans’ sign assessment.

6. Elevate the legs during the imaging pro-cedure, which takes about 10 minutes.

7. Just before beginning the procedure, take a “time out” to verify the correct client, procedure, and site.

Procedure1. The client’s legs are elevated during scan-

ning to prevent pooling of blood in the veins of the legs.

2. 125I-labeled fibrinogen is injected intrave-nously, and serial scans are performed on each leg 1, 4, 24, and 48 hours afterward. Surface radioactivity may be measured daily for as long as 2 days.

3. The extremity is marked in segments along the course of the vein tract.

4. Areas of fibrinogen incorporation into a thrombus are detected with the counter as areas exhibiting increased radioactivity, indicating increased concentration of radioactive tracer.

Postprocedure Care1. Maintain bed rest if thrombi are detected.2. Do not wash off markings on the

extremity.3. Assess the venipuncture site for

infiltration.4. Assess for swelling in the calf, tenderness,

and cyanosis of the skin.5. Observe the client carefully for up to 60

minutes after the study for a possible (ana-phylactic) reaction to the radionuclide.

6. For 24 hours after the procedure, wear rubber gloves when discarding urine. Wash the gloved hands with soap and water before removing the gloves. Wash the ungloved hands after the gloves have been removed.

Client and Family Teaching1. This test involves several leg scans after

the client receives an intravenous tracer that shows up on the scan. Scanning may continue for up to 2 days after the injection.

2. The test poses no risk of radioactive damage to the client.

Norm. No evidence of thrombi. No areas of abnormal concentration in the deep veins of the lower legs.

Usage. Used to monitor the development and progression of deep vein thromboses. Longitudinal screening for clients at risk for thrombotic processes.

Positive. Deep vein thrombosis, thrombo-phlebitis, and thrombosis.

Negative. Normal finding. Also negative after the active clotting process has stopped.

Description. Fibrinogen (factor I) is a complex polypeptide that converts to the insoluble polymer of fibrin after thrombin enzymatic action and combines with plate-lets to clot the blood. The 125I-labeled fibrin-ogen leg scan is an invasive, nuclear medicine test involving the intravenous injection of radionuclide-labeled fibrinogen (fibrinogen labeled with radioactive iodine) and scan-ning with a well counter for subsequent incorporation of the radioactive material into a thrombus. The scan measures increased surface radioactivity (>20%), which indicates uptake by thrombi in the leg(s). The test is most useful in detecting actively forming thromboses of the calf; 85% of positive results are seen within the first 24 hours after the calf is injected with iodine-125.

Professional ConsiderationsConsent form IS required.

RisksInfection, allergic reaction to radiolabeled fibrinogen (itching, hives, rash, tight feeling in the throat, shortness of breath, broncho-spasm, anaphylaxis, death).ContraindicationsAnticoagulant therapy, bleeding disorders, thrombocytopenia, during pregnancy or breast-feeding, previous allergy to radiola-beled albumin.

Preparation1. Ten drops of Lugol’s solution in juice are

given to block thyroid gland uptake of the radioactive tracer.

2. Establish 18-gauge intravenous access.3. Have emergency equipment readily

available.

Immune Complex Assay—Blood 671

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3. Maintain bed rest until deep venous thrombosis (DVT) has been ruled out.

4. Meticulously wash hands with soap and water after each void for 24 hours.

Factors That Affect Results1. False-negative results may occur where

active clot formation is completed, but the thrombus still remains.

2. Usually 1-2 days are required for enough radiolabeled fibrinogen to be incorpo-rated into the clot before the clot can be detected.

3. Thrombi of the pelvis are difficult to detect with this test.

4. False-positive results may occur in clients with bacterial inflammatory conditions of the lower extremities.

5. A radioactive test within the previous 24 hours invalidates the results.

6. Up to 72 hours may elapse before the results become positive.

Other Data1. Other tests to detect DVT are Doppler

ultrasonography, venography, thermog-raphy, perfusion lung scan, gas ventilation lung scan, and pulmonary angiography.

2. This test is insensitive to upper thigh and pelvic vein thrombosis.

3. Rate of thrombosis is significantly less with laparoscopic intervention only.

4. Health care professionals working in a nuclear medicine area must follow federal standards set by the Nuclear Regulatory Commission. These standards include precautions for handling the radioactive material and monitoring of potential radiation exposure.

5. Iodine-125 half-life is 60 days.

ImipramineSee Tricyclic Antidepressants—Plasma or Serum.

Immune Complex Assay—BloodNorm. Complexes not detected.C1q binding: <13%.Raji cell assay: <50 g of aggregated human gamma globulin equivalents (AHG).

Positive. Arthritis (rheumatoid), biliary cirrhosis, dengue fever, disseminated gon-orrhea, endocarditis, glomerulonephritis, Hansen’s disease (leprosy), Hodgkin’s disease, leukemia, malaria, malignant mela-noma, pulmonary fibrosis, schistosomiasis, serum hepatitis, serum sickness, Sjögren’s syndrome, and systemic lupus erythemato-sus (SLE).

Description. Complements are proteins that, when activated, assist the cell lysis func-tion of antibodies. Activation of comple-ment by an antigen-antibody response is called the “classical pathway.” Complement activation independent of antibody, initiated by complement binding to the surfaces of infectious organisms, is known as the “alter-native pathway.” Both pathways ultimately result in the complement cascade’s forma-tion of the membrane attack complex

(MAC). This radioimmunoassay (RIA) test is helpful in diagnosing autoimmune and infectious inflammatory disease processes.


Preparation1. Tube: Red topped, red/gray topped, or

gold topped.

Procedure1. Draw a 2-mL blood sample.

Postprocedure Care1. Write the collection time and date on the

laboratory requisition.

Client and Family Teaching1. Results are normally available within 2

days.

Factors That Affect Results1. Reject specimens received more than 1

hour after collection.2. Certain cryoglobulins, cold agglutinins,

rheumatoid factors, and paraproteins may cause false-positive results.

672 Immunochemical Fecal Occult Blood Testing (iFOBT, Fecal Immunochemical Testing, FIT)—Stool

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Other Data1. There are specific assays to measure differ-

ent populations of immune complexes.2. Also see Raji cell and immune complex

assay—Blood.

3. Clinical information and physical find-ings may be the first sign of an immune complex disorder.

4. See also TA90 immune complex assay— Serum.

Immunochemical Fecal Occult Blood Testing (iFOBT, Fecal Immunochemical Testing, FIT)—StoolNorm. Negative

Usage. Screening for colon cancer in average risk individuals. Not for use in indi-viduals known to have an increased risk of colon cancer. Specific for detection of occult bleeding in the large colon.

Description. In contrast to traditional fecal occult blood testing, which detects the heme portion of red blood cells, immunochemical testing for blood in the stool uses of anti-body binding to hemoglobin. Since globin from the upper gastrointestinal tract does not normally survive passage into the lower intestine, this test is specific for identifying lower gastrointestinal bleeding. iFOBT tests offer advantages over traditional FOBT for individuals (Allison and Potter, 2009) of average risk for colorectal cancer. The tests can detect bleeding in smaller amounts (as small as 0.3 ml/day) and are not affected by dietary intake or drugs such as NSAIDs or Vitamin C. In addition, they provide higher sensitivity (69%-100%) than traditional fecal occult blood testing (FOBT) (11%-68%) for detection of colorectal cancer and pre-cancerous adenomas in individuals of average risk for these conditions. Sensitivity can be less than traditional FOBT in indi-viduals with an increased risk. Finally, test collection is simpler than other methods of fecal occult blood testing; thus, is well suited to self-collection of an at-home specimen.


Preparation1. Obtain test kit.2. No dietary restriction is needed.

Procedure1. Place collection sheet or receptacle over

the toilet.2. Sample should be collected without

allowing the stool sample to come into contact with the water in the toilet.

3. After defecation, twist open the cap of the sampling bottle, then scrape the stool in a circular motion with the testing probe. Make sure that the grooved portion of the probe is covered with stool, then insert the test probe into the sampling bottle, snapping the lid on tightly.

4. Flush the collection sheet and the remain-ing stool.

Postprocedure Care1. Complete the label with individual iden-

tifying information. Then insert the sam-pling bottle into the mailing envelope and mail to the lab for testing.

Client and Family Teaching1. Mail the sample promptly.2. To reduce the chance of a false negative,

daily samples collected over a 2-3 day period can be tested.

Factors That Affect Results1. False negative results can occur when

there is a delay in processing the speci-men, or in the presence of colorectal cancer that does not or has not yet caused sufficient bleeding or that only bleeds intermittently.

2. Results are less likely than FOBT to be positive when the source of blood in the stool is from the upper gastrointesti-nal tract because the enzymes in the upper GI tract degrade globin, the target of this test.

Other Data1. Because of the simplicity of sample col-

lection, improved patient follow-through rates are seen when this test is used.

2. Colorectal cancer is the second highest cause of death from cancer in the United States. Populations that have lower than average rates of testing are those that have diabetes, are obese, or are current or former smokers.

Immunofluorescence, Skin Biopsy—Specimen 673

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3. Brand names of iFOBT tests include InSure (Enterix), Instant-View (Alpha Scientific Designs), immoCARE (Care Products, Inc.), MonoHaem (Chemicon

International), and OC-Auto Micro (Polymedco).

4. See also ColoSure™ test—Stool; Occult blood—Stool.

Immunoelectrophoresis—Serum and UrineNorm. Serum: No abnormal proteins present.Urine: No abnormal proteins present; requires pathologist’s interpretation.

Usage. Dysproteinemia, Hodgkin’s disease, humoral immune deficiency, multiple myeloma, renal failure, and Waldenström’s macroglobulinemia.

Description. A sample of serum or urine is placed on a slide containing agar gel, and an electrical current is passed through the gel, causing separation according to different electrical charges in each immunoglobulin: IgG, IgA, IgM, IgD, and IgE. Each immuno-globulin develops a band that has a certain curvature, position, and intensity of color. Abnormalities in any immunoglobulin cause the band for that precipitation to be displaced, bowed, lighter in color, thicker, or absent. After protein electrophoresis, anti-sera to immunoglobulins G, A, and M and to kappa and lambda light chains are applied to a urine sample to confirm and identify a suspected monoclonal protein or the pres-ence of Bence Jones proteins (free kappa or lambda light chains).


Preparation1. For serum: Tube: red topped, red/gray

topped, or gold topped. For urine: Sterile urine collection container.

2. Record any vaccinations or immuniza-tions within the previous 6 months on the laboratory requisition.

3. Record any blood or blood component therapy within the previous 6 weeks on the laboratory requisition.

Procedure1. For serum test: Draw a 4-mL blood sample.2. For urine test: Obtain a 12-mL urine

sample in a sterile container.

Postprocedure Care1. Refrigerate the urine; send it to the labo-

ratory within 2 hours.


hours.

Factors That Affect Results1. Anticoagulants, anticonvulsants, hydrala-

zine, oral contraceptives, and phenylbuta-zone affect the thickness of the bands, causing difficult interpretation in serum tests.

2. Chemotherapy and radiation treatments affect color and thickness of the bands, adding difficulty to the interpretation of the serum test.

Other Data1. This is a valuable initial screening tool for

identifying diseases with altered protein fractions.

2. The urine test cannot be performed if urine protein is <60 mg/L or if urine protein electrophoresis is normal.

Immunofluorescence, Skin Biopsy—SpecimenNorm. Requires interpretation.

Positive. Collagen disease, dermatitis her-petiformis, immune complex glomerulone-phritis, immune disorders of the lung, Kindler syndrome, lupus, malignant lym-phoma, multiple myeloma, pemphigus, Waldenström’s macroglobulinemia, Wegen-er’s granulomatosis.

Negative. Keratinized tissue.

Description. This procedure uses fluores-cent light to visualize tissue and sub-epidermal blood vessels for the presence of complement, immunoglobulins, and immune complexes containing antibodies and their antigens. Immune complexes are present in many autoimmune diseases, and

674 Immunoglobulin A (IgA)—Serum

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identification of their presence in skin speci-mens can help to differentiate a diagnosis.

Professional ConsiderationsConsent form IS required for the procedure used to obtain the specimen. See Biopsy, Site-specific—Specimen for procedure-specific risks and contraindications.

Preparation1. Obtain covered saline-soaked gauze or

filter paper, a punch biopsy instrument, ice or a petri dish, and a local anesthetic.

2. The container must be labeled with the client’s identification information and the date.

3. See Biopsy, Site-specific—Specimen.

Procedure1. Local anesthetic may be injected into the

biopsy site.2. A 3-mm punch biopsy of tissue is col-

lected and placed on ice or in a petri dish containing 0.9% saline.

Postprocedure Care1. Send the moistened tissue sample to the

laboratory immediately to be quickly frozen in liquid nitrogen.

2. The site may be left open to air or covered with a dry, sterile dressing.

Client and Family Teaching1. Keep the site clean and dry and report any

signs of infection, such as redness, pain (severe) for more than 24 hours, swelling, or purulent drainage.

2. Keep the site covered with a Band-Aid or gauze for 2 days, and then leave the site open to air.

3. Call the physician if there is bleeding amounting to more than a small area on the dressing, or bleeding that will not stop after pressure is applied for 5-10 minutes.

4. Use a mild analgesic as prescribed, if nec-essary, for site tenderness.

Factors That Affect Results1. Reject specimens in a fixative or any that

have dried out.

Other Data1. Failure to detect IgG may be attributed to

an infectious or inflammatory process in the sampled tissue.

2. Repeated biopsies may be necessary for diagnosis of dermatitis herpetiformis.

3. Skin biopsy in combination with histo-pathologic examination yields the best diagnostic results.

4. Submit an additional specimen in forma-lin for light microscopy.

Immunoglobulin A (IgA)—SerumNorm.

SI UnitsAdults 90-400 mg/dL 0.9-4.00 g/L

ChildrenNewborn 0-5 mg/dL 0-0.05 g/LInfants, 25% of adults 0-11 mg/dL 0-0.11 g/L1-3 months 7-34 mg/dL 0.07-0.34 g/L4-6 months 10-46 mg/dL 0.10-0.46 g/L7-12 months 19-55 mg/dL 0.19-0.55 g/L13-24 months 26-74 mg/dL 0.26-0.74 g/L25-36 months 34-108 mg/dL 0.34-1.08 g/L3 years, 50% of adults3-5 years 66-120 mg/dL 0.66-1.20 g/L6-8 years 79-169 mg/dL 0.79-1.69 g/L9-11 years 71-191 mg/dL 0.71-1.91 g/L12-16 years 85-211 mg/dL 0.85-2.11 g/L>16 years 90-400 mg/dL 0.9-4.00 g/L

Increased. Arthritis (rheumatoid), auto-immune disorders, Berger’s disease, carci-noma, chronic infections, cirrhosis,

dysproteinemia, Henoch-Schönlein purpura, multiple myeloma, polio, sinusitis, and Wiskott-Aldrich syndrome.

Immunoglobulin A (IgA) Antibodies—Serum 675

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Decreased. Bruton’s disease, burns, child-hood asthma, congenital IgA deficiency, hereditary ataxia telangiectasia, humoral immunodeficiency, hypogammaglobulinemia, nephrotic syndrome, and protein-losing enter-opathies. Drugs include carbamazepine, dextran, estrogens, gold, methylprednisolone, oral contraceptives, penicillamine, phenytoin, and valproic acid.

Description. Immunoglobulin A (IgA) exists in both serum and secretory forms. IgA is the antibody effective against viruses and certain bacteria such as Clostridium tetani, Corynebacterium diphtheriae, and Escherichia coli. With an area of response localized primarily to mucosal membranes, it is the main immunoglobulin in colostrum, saliva, tears, and secretions of the bronchial, gastrointestinal, genitourinary, and respira-tory tracts. IgA has been found in receptors on alveolar macrophages and on leukocytes and is most recently thought to perform a broad protective function in the respiratory tract. It protects by neutralizing invading viruses at the apical surface of endothelium after infection. In the blood, IgA normally constitutes 10%-15% of client’s total serum immunoglobulins.



gold topped.2. Write the client’s age on the laboratory

requisition.


Postprocedure Care1. Refrigerate the specimen if it is not pro-

cessed immediately.


hours.

Factors That Affect Results1. Reject hemolyzed or turbid samples.

Other Data1. IgA does not cross the placenta.2. Clients with congenital IgA deficiency

may develop anaphylaxis if transfused with blood products containing IgA.

3. Secretory IgA is under investigation for production rate in response to varying conditions. More than one study has found an increase in production of sali-vary IgA after subjects performed pro-gressive relaxation techniques.

Immunoglobulin A (IgA) Antibodies—SerumNorm. Antibody not present (negative).

Positive. Anaphylactic transfusion reaction in IgA-deficient individual; disease-specific IgA antibodies indicate past infection.

Description. Antibody formed against IgA when IgA is introduced into the bloodstream of a client with a congenital IgA deficiency. The IgA is recognized as a foreign antigen, with resultant action of IgG antibodies attacking it, causing anaphylaxis. Testing for IgA antibodies should be performed in all anaphylactic trans-fusion reactions. A particle gel immunoassay method being tested shows promise for rapid, sensitive, and reproducible detection of IgA antibodies, which can help to quickly confirm IgA transfusion reaction. Other uses for IgA antibody testing are to determine whether a client has had a past infection from a specific organism, such as Actinomyces, Chlamydia pneumoniae, Entamoeba histolytica, measles, polio, or Toxoplasma gondii.



gold topped.


Postprocedure Care1. Give the client a wallet card, specifying

the IgA deficiency.

Client and Family Teaching1. If the test is positive, any future blood

transfusions must be IgA deficient or else a severe allergic reaction will occur.

Factors That Affect Results1. Temperature of specimen not held at 37

degrees C.

Other Data1. None.

676 Immunoglobulin D (IgD)—Serum

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Immunoglobulin D (IgD)—SerumPreparation1. Tube: Red topped, red/gray topped, or


requisition.


Postprocedure Care1. None.


hours.

Factors That Affect Results1. A chylous serum sample invalidates the

results.

Other Data1. 75% of IgD is in the intravascular

compartment.2. 90% of multiple myelomas are of the

IgD type.

Norm. Composes <1% of client’s serum immunoglobulins.

SI UnitsAdult 0-8.0 mg/dL 5-30 µg/LNewborn <1.0 mg/dL <10 µg/L

Increased. Chronic infections, connective tissue disease, dysproteinemia, and IgD myeloma.

Decreased. Acquired immunodeficiency syndrome. Drugs include phenytoin.

Description. Immunoglobulin D is a protein that may act as an autoimmune anti-body in clients with collagen disease. The true biologic function of IgD is unknown but is suspected to play a role in the induc-tion of humoral response and tolerance. The utility of this test is limited, because abnor-mal findings are rare.


Immunoglobulin E (IgE)—SerumNorm.

IU/mL U/mL SI Units (µg/L)Adults 3-423 4.2-592 10-142115-20 years 6.8-39.6 1.5-384 3.60-921.621-40 years 20.3-36.5 0.9-239 2.20-573.641-60 years 26-53 1.2-324 2.90-777.661-87 years 16.2-43.8 0.7-197 1.70-472.8ChildrenCord blood 0.1-1.5 0.1-2 0.24-4.86 weeks 0.1-2.8 0.1-4 0.24-9.66 months 0.9-28 0.1-56 0.24-134.41 year 1.1-10.2 0.1-83 0.24-199.24 years 2.4-34.8 0.4-144 0.96-345.610 years 0.3-215 1.9-421 4.56-1010.414 years 1.9-159 1.6-456 3.84-1094.4

Increased. Alcohol intake (moderate or more), allergic rhinitis, asthma, atopic derma-titis, bronchopulmonary aspergillosis, eczema, food and (some) drug allergies, hay fever, IgE myeloma, insect sting allergy, occupations with high exposure to hairdressing chemicals, latex allergy, paracoccidioidomycosis, parasitic

infections, pemphigoid, periarteritis nodosa, postoperatively (early phase, correlating with severity of surgical injury), sinusitis, visceral leishmaniasis, and Wiskott-Aldrich syndrome. Drugs include gold compounds. Herbal or natural remedies include documented reac-tions to garlic or Echinacea.

Immunoglobulin G (IgG)—Serum 677

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Decreased. Advanced carcinoma, agam-maglobulinemia, alcoholics (after ethanol abstinence), ataxia-telangiectasia, and IgE deficiency. Drugs include phenytoin sodium. Herbal or natural remedies include shoseiryu-to (“minor blue dragon combina-tion,” syo-seiryu-to, xiao-qing long-tang, composed of Pinellia, ma huang [yellow vetch], peony, licorice, cinnamon bark, wild ginger [Asarum], schizandra [Schisandra], and ginger [Panax]).

Description. Immunoglobulin E is the antibody protein primarily responsible for allergic reactions such as hay fever, asthma, and allergies to foods and drugs, as well as atopic reactions such as latex allergies. When inhaled or ingested, IgE comes into contact with and activates the mast cells in the respi-ratory and gastrointestinal tracts and causes a histamine response in the body.




requisition.


Postprocedure Care1. Handle the tube carefully because hemo-

lysis invalidates the test.

Client and Family Teaching1. IgE level is elevated in approximately half

of people with allergies.

Factors That Affect Results1. The test should not be performed if the

client has undergone a radionuclide scan within the previous 72 hours.

2. Levels increase during allergic reactions and disease processes described previ-ously, and decrease as symptoms subside and clinical conditions improve.

Other Data1. 50% of IgE is intravascular.2. Normal IgE levels do not exclude allergic

phenomena.3. IgE normally constitutes <0.1% of the cli-

ent’s immunoglobulins.4. Among investigational treatments being

studied for allergic conditions are an anti-IgE therapy using immunoglobulin directed against IgE and the use of diso-dium cromoglycate for reduction of IgE production.

Immunoglobulin G (IgG)—SerumNorm. Normally constitutes 75% of client’s total immunoglobulins.


ChildrenCord blood 650-1600 mg/dL 6.5-16.0 g/L1 month 250-900 mg/dL 2.5-9.0 g/L2-5 months 200-700 mg/dL 2.0-7.0 g/L6-9 months 220-900 mg/dL 2.2-9.0 g/L10-12 months 290-1070 mg/dL 2.9-10.7 g/L1 year 340-1200 mg/dL 3.4-12.0 g/L2-3 years 420-1200 mg/dL 4.2-12.0 g/L4-6 years 460-1240 mg/dL 4.6-12.4 g/L>6 years 650-1600 mg/dL 6.5-16.0 g/L

Increased. Infections (chronic or recur-rent), liver disease (chronic), malignancies (lymphomas), multiple myeloma, pulmo-nary tuberculosis, rheumatoid arthritis, sar-coidosis, systemic lupus erythematosus, toxoplasmosis, and Waldenström’s disease. The IgG titer is usually elevated in clients

with Helicobacter pylori, indicating active infection.

Decreased. Acquired immunodeficiency syndrome, aplastic anemia, humoral immunodeficiency, and Wiskott-Aldrich syndrome.

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678 Immunoglobulin G (IgG) Synthesis Rate, Cerebrospinal Fluid

Description. Immunoglobulin G is com-prised of four subclasses, IgG1 through IgG4, and constitutes 75% of all immuno-globulins in the bloodstream. IgG possesses antibody activity against viruses, some bac-teria, and toxins. It is able to cross the pla-centa and provide immunity to a developing fetus and also serves as an activator of the complement system. IgG levels increase in response to infection and remain elevated, even if the infection becomes chronic. IgG is also important in autoimmune diseases because many of the autoantibodies belong in this class. This test evaluates humoral immunity and monitors therapy in IgG myeloma. Various forms of IgG assays are designed to pinpoint disease-specific IgG antibodies for a variety of infections. Sub-class measurement and evaluation of IgG is not useful because clients with subclass defi-ciency often show normal IgG function.



gold topped.

2. Write the client’s age on the laboratory requisition.


Postprocedure Care1. None required.


hours.

Factors That Affect Results1. Specimens should be stored at 37

degrees C.

Other Data1. IgG is the only immunoglobulin that

crosses the placenta.2. Laboratory-based serology titers should

be obtained to quantitate the antibody level and establish a baseline when treat-ment for H. pylori is planned. This allows for follow-up after therapy, which, if suc-cessful, will usually show a consistent fall in IgG titer levels.

3. A dipstick dye immunoassay is available to detect IgG and IgM antibodies in toxoplasmosis.

Immunoglobulin G (IgG) Synthesis Rate, Cerebrospinal FluidSee Cerebrospinal Fluid, Immunoglobulin G, Immunoglobulin G Ratios and Immunoglobulin G Index, Immunoglobulin G Synthesis Rate—Specimen.

Immunoglobulin M (IgM)—SerumNorm. Normally constitutes 5%-10% of the client’s total immunoglobulins.


ChildrenCord 0-19 mg/dL 0.000.19 g/L1-3 months 7-78 mg/dL 0.07-0.78 g/L3-6 months 19-72 mg/dL 0.19-0.72 g/L6-12 months 21-104 mg/dL 0.21-1.04 g/L1-2 years 19-148 mg/dL 0.19-1.48 g/L2-3 years 40-151 mg/dL 0.40-1.51 g/L3-5 years 28-142 mg/dL 0.28-1.42 g/L5-8 years 30-162 mg/dL 0.30-1.62 g/L8-12 years 24-161 mg/dL 0.24-1.61 g/L12-16 years 26-221 mg/dL 0.26-2.21 g/LPregnancy IgM development during pregnancy occurs at an

increase of 0.5 mg/dL per week of gestation.

Indican—Urine 679

I

Increased. Biliary cirrhosis, collagen vas-cular disease, cutaneous leishmaniasis, cytomegalovirus, dysproteinemia, hyperim-munoglobulin M syndrome (HIGM), infec-tion (bacterial, parasitic), leptospirosis, Lyme disease, reticulosis, rheumatoid arthritis, sarcoidosis, toxoplasmosis, try-panosomiasis parasite, and Waldenström’s macroglobulinemia. Drugs include chlor-promazine.

Decreased. Humoral immunodeficiency, hypogammaglobulinemia, multiple myeloma IgA or IgG, and protein-losing enteropathy. Drugs include carbamazepine and dextran.

Description. Immunoglobulin M is the first antibody to appear after an antigen enters the body and is active against gram-negative organisms and rheumatoid factors. IgM forms the natural antibodies such as those to the ABO blood groups. The IgM molecule is too large to cross the placenta; thus it does not help provide fetal immunity to antigens. If levels are elevated in cord blood samples, it may indicate that the infant was infected before birth with organ-isms that can cause birth defects, such as Toxoplasma gondii, cytomegalovirus, or togavirus (causing rubella). This test is used to screen for congenital infections and to help diagnose and monitor infections.



gold topped.




hours.

Factors That Affect Results1. Specimen storage at a temperature other

than 37 degrees C may cause falsely decreased results.

2. IgM responses may remain positive for up to 20 years after a client has had Lyme disease.

Other Data1. A dipstick dye immunoassay is available

to detect IgG and IgM antibodies in toxo-plasmosis. A dipstick assay that detects IgM antibodies in brucellosis is much less sensitive (28%) than the standard serum agglutination test (87%).

Indentation TonometrySee Tonometry Test for Glaucoma—Screen.

Indican—UrineNorm. <220 µmol in 24 hours, or negative.

Positive. Hartnup disease and ileal dysfunction.

Negative. Normal protein catabolism or intestinal absorption.

Description. Indican is a tryptophan metabolite that is excreted mostly in the feces but also in small amounts in the urine as a result of absorption and detoxification of indole produced by bacterial action on tryptophan in the intestines. The presence of

indican in the urine indicates amino acid malabsorption.


Preparation1. Obtain a sterile plastic container.2. A sample from a first-morning void or

an aliquot of a 24-hour collection is preferred.

Procedure1. Collect at least a 6-mL or a random urine

specimen in a sterile plastic container.

I

680 Indirect Antiglobulin Test

Postprocedure Care1. Transport the specimen to the laboratory

within 1 hour after collection and refrig-erate until testing.


hours.

Factors That Affect Results1. Results are invalid if the urine is not deliv-

ered to the laboratory within 1 hour after collection.

Other Data1. Increased indican may cause the urine

specimen to blacken in color over time.

Indirect Antiglobulin TestSee Coombs’ Test, Indirect—Serum.

Infectious Mononucleosis Screening TestSee Heterophil Agglutinins—Blood.

Infertility Screen—SpecimenNorm.Multiplex polymerase chain reaction test: NegativeAntisperm antibody test: Negative for sperm agglutinating antibodySemen analysis: See Semen analysis—Specimen

Usage. Evaluation for possible causes of infertility.

Description. The infertility screen includes tests of sperm function, antisperm antibody detection, and a genetic test to detect dele-tion of the Y chromosome long arm DAZ (deleted in azoospermia) gene. This screen may be done alone or as part of a full infer-tility evaluation that narrows down causes of infertility into the following common cate-gories: abnormal sperm function, abnormal ovulation, tubal dysfunction, antisperm antibodies, and genetic causes. For evalua-tion of sperm function, semen is analyzed for the presence, number, volume, motility, morphology, and liquefaction time of sperm. To test for the presence of antisperm antibod-ies, spermatozoa, cervical mucus, and both male serum and female serum are analyzed using an enzyme-linked immunosorbent assay, mixed antiglobulin reaction (MAR) with or without immunobead-binding tests, which can identify IgG, IgA, and IgM anti–sperm antibodies. These antibodies have been linked to infertility and are believed to interfere with the interaction of the sperm and the egg and to block the sperm from passing through cervical mucus. Genetic

testing includes identifying micro deletions from specific regions of the Y chromosome and identification of a congenital bilateral absence of the vas deferens, which is associ-ated with the cystic fibrosis gene. Micro deletions are present to a greater extent in azoospermic men than in men with less severe spermatogenic infertility. Micro dele-tions reduce fertility. Other testing com-monly included in infertility evaluation includes vaginal, endometrial, or semen culture for Chlamydia trachomatis, ovula-tion evaluation, laparoscopy, hysterosalpin-gography, the Sims-Huhner test, and postcoital testing. Less common testing methods sometimes used include hormonal testing, pelvic ultrasonography, hysteros-copy, cervical cultures, and endometrial biopsy.

Professional ConsiderationsInformed consent is recommended for genetic testing.

Preparation1. Obtain a tube for each partner: Red

topped, red/gray topped, or gold topped.2. See Semen analysis—Specimen.3. See Client and Family Teaching.

Influenza A and B Titer—Blood 681

I

Procedure1. Obtain a 7-mL blood sample from each

partner.2. See Semen analysis—Specimen.

Postprocedure Care1. Explain that repeat testing may be

necessary.2. See Semen analysis—Specimen.

Client and Family Teaching1. See Semen analysis—Specimen.2. Refer to Appendix B, “Informed Consent

for Genetic Testing”.3. Clients with positive genetic tests should

be referred for follow-up genetic counseling.

Factors That Affect Results1. Repeat testing may be necessary because

results vary with samples.

Other Data1. The infertility rate is about 15%, with the

most frequent cause being of genetic origin in the male.

2. The Genetic Information Nondiscrimina-tion Act of 2008 prohibits health plans from using genetic family history or genetic test results from influencing eligibility or pre-miums for health insurance. It also prohib-its employers from using this information to influence decisions about hiring, termi-nating employment, or employment pay, promotions, or privileges.

3. See also Semen analysis—Specimen.

Influenza A and B Titer—BloodNorm. Less than a fourfold increase in titer in paired sera. Less than 1 : 8 titer indicates previous exposure.

Positive. Influenza.

Negative. Bacterial infections.

Description. Influenza viruses are typed for epidemiologic surveys. Both viruses, A and B, cause major epidemics every 2-4 years, as antigenic shifts occur, leaving the population susceptible to reinfection by a different strain. Virus B usually is sporadic and local, whereas virus A spreads rapidly and to all population areas. The influenza titer evaluates the body’s response to influ-enza immunization.



gold topped.

Procedure1. Draw a 7-mL blood sample at the onset

of symptoms.2. Draw a convalescent sample 14 days later.


Client and Family Teaching1. Return in 2 weeks for a second sample to

be drawn. This helps monitor recovery.

2. Annual influenza vaccinations are recom-mended in the latter portions of each year for the elderly, health care workers, and others at high risk for exposure to the influenza virus.

Factors That Affect Results1. Failure to collect a convalescent sample

limits the value of the acute sample results.

2. Immune response to the vaccine is less in those that have received previous influ-enza vaccination than in those receiving it for the first time.

3. The immune response to the influenza vaccine is impaired in clients who have received liver transplants.

Other Data1. Serologic diagnosis is not necessary

during an epidemic but is valuable for epidemiologic purposes.

2. Influenza vaccination is typically not very effective in those ≥80 years old. One study found immune response in this popula-tion to be enhanced in those given nutri-tional supplementation. Another study found that in the elderly, vitamin E levels are significantly correlated with an intact immune response to influenza immunization.

3. Intranasal and intradermal vaccines have been found equivalent to the intramuscu-lar route in stimulating the immune response.

I

682 Inhibition Level of Antibiotic

Inhibition Level of AntibioticSee Schlichter Test—Specimen.

INRSee Prothrombin Time and International Normalized Ratio—Blood.

Insulin and Insulin Antibodies—Bloodstandardization of the test method vary widely by laboratory.)

Norm. Free insulin: fasting ≤25 µIU/mL (<172.5 pmol/L, SI units). (Norms and

Insulin Level via Radioimmunoassay

SI UnitsAdult, fasting level <17 µIU/mL or 1.00 mg/L <117 pmol/LNewborn 3-20 µIU/mL 21-139 pmol/LInfant <13 µIU/mL ≤89 pmol/LPrepubertal child <13 µIU/mL ≤89 pmol/LPanic levels >30 µIU/mL >207 pmol/LLast trimester, amniotic fluid 11.3 µIU/mL 78 pmol/L

Insulin Antibodies. Undetectable to less than 4% when using either bovine or porcine insulin as a reagent. Insulin antibodies have been shown to occur more frequently with aging and more in females than in males.

Increased Insulin. Acromegaly, Beckwith-Wiedemann syndrome, beta-cell adenoma, Cushing’s syndrome, dystrophia myotonica, familial fructose and galactose intolerance, hyperinsulinism, hypoglycemia, insulin-resistance syndromes, insulinoma, liver disease, metabolic syndrome, nesidioblasto-sis, non–insulin-dependent diabetes melli-tus, obesity, overdose of insulin, pancreatic islet cell lesion, and pheochromocytoma. Drugs include albuterol, calcium gluconate in the newborn, estrogen, fructose, glucagon, glucose, insulin, levodopa, medroxyproges-terone, oral contraceptives, prednisolone, quinidine, quinine, spironolactone, sucrose, terbutaline, tolazamide, and tolbutamide.

Decreased Insulin. Diabetes mellitus, hyperglycemia, hypopituitarism, and pancreatectomy-induced diabetes. Drugs include asparaginase, beta-adrenergic block-ers, calcitonin, cimetidine, diazoxide, ethac-rynic acid, ether, ethyl alcohol (ethanol), furosemide, metformin, nifedipine, phen-formin, phenobarbital, phenytoin, and thia-zide diuretics.

Positive Insulin Antibodies. Factitious hypoglycemia, autoimmune insulin syn-drome (AIS).

Panic Level Symptoms and TreatmentSymptoms. Diaphoresis, dizziness, faint-ness, pallor, weakness, progressing to stupor and seizures.

TreatmentNote: Treatment choice(s) depend(s) on client’s history and condition and episode history.1. Administer 50% dextrose in water

(D50W) by 50-mL IV injection, followed by carbohydrate and protein foods.

2. Follow with D10W infusion if NPH or other long-acting insulin was taken.

3. Administer glucagon IV if the client has normal liver function.

4. Take bedside or laboratory glucose mea-surement hourly.

5. If serum potassium level is low or cardiac dysrhythmias are present, give KCl infusion.

6. Hemodialysis and peritoneal dialysis will NOT remove insulin.

Insulin and Insulin Antibodies—Blood 683

I

Negative Insulin Antibodies. Normal finding. Also negative in insulinoma.

Description. Insulin is a hormone that regulates carbohydrate metabolism. It is produced in the pancreas by the beta cells of the islets of Langerhans, and its rate of secre-tion is determined primarily by the level of blood glucose. The radioimmunoassay test measures endogenous insulin by using a series of tubes containing a fixed amount of antibody label and an aliquot of standard, control, or unknown. The client’s unlabeled antigen in the blood competes with labeled antigen for antibody-binding sites. The per-centage of antigen bound to antibody is related to the total antigen present and is reflected by the distribution of a radioactive label. Low immunoreactive insulin levels have been associated with a higher risk of developing degenerative diseases such as atherosclerosis, hypertension, and dyslipid-emia. Insulin antibodies, also referred to as anti–insulin-Ab, may be present in diabetic clients treated for several weeks or more with conventional insulin. These antibodies may also be present in persons who have never received insulin but have autoimmune insulin syndrome (AIS), a rare condition characterized by hyperinsulinemia and hypoglycemia. For diabetic clients, this test may be used with C-peptide to determine whether hypoglycemia is caused by insulin abuse. Insulin antibodies are transferred through the placenta and are present in 30%-50% of children at the time of diagno-sis before beginning insulin therapy.



gold topped. Also obtain ice.2. Specimens MAY be drawn during

hemodialysis.3. See Client and Family Teaching.

Procedure1. Draw a 7-mL blood sample. Place the

sample immediately on ice.

Postprocedure Care1. Resume diet and any medications held

before the test.2. Assess the client for signs of hypoglyce-

mia, which could occur as a response to fasting.

Client and Family Teaching1. This test is used to evaluate for insulin-

producing neoplasm (islet cell tumor, insulinoma) or to evaluate insulin pro-duction in diabetes mellitus.

2. Fast from food and fluids (except water) for 8 hours before the test.

3. Do not take insulin before the test.4. Review the procedure used to obtain the

blood sample, including the fact that some discomfort may be experienced when the needle enters the skin.

Factors That Affect Results1. Reject specimens if the client had a

radioactive scan within 7 days before the test.

2. Hemodialysis destroys insulin.3. Specimen hemolysis invalidates the

results.4. Falsely elevated results have been found

when insulin antibodies are present in the blood when the radioimmunoassay testing method is used. More accurate results are obtained when the immunora-diometric assay testing method is used if insulin antibodies are suspected.

5. Values are higher in plasma samples than in serum.

6. Elevated levels have been found in men with elevated C-reactive protein levels.

Other Data1. Serum insulin level is commonly pre-

scribed with serum glucose level to confirm functional hypoglycemia, uncon-trolled insulin-dependent diabetes melli-tus, or fasting hypoglycemia of unknown cause.

2. The norms and standardization of the test method vary widely by laboratory.

3. Undetectable in amniotic fluid during the first trimester.

4. Complete absence of insulin during the last trimester of pregnancy is associated with intrauterine death.

5. Some studies evaluating the relationship of C-reactive protein, glucose, and Hb A1c indicate a possible role of inflammation in insulin resistance.

6. When insulin antibodies are present, the test of choice is C-peptide to determine whether exogenous insulin administra-tion is being abused. If C-peptide levels are not elevated, endogenous insulin secretion has not increased.

684 Insulin-like Growth Factor-I (IGF-I)—Blood

I

7. There is some discussion in the literature concerning possible increased stimula-tion of insulin antibodies when the

inhaled route of insulin is used versus the subcutaneous route.

Increased. Acromegaly, diabetic retinopa-thy, gigantism, hyperpituitarism, obesity, pituitary gigantism, precocious puberty, and pregnancy.

Decreased. Anorexia nervosa, chronic illness, cirrhosis, delayed puberty, diabetes mellitus, emotional deprivation syndrome, hepatoma, hypopituitarism, hypothyroid-ism, kwashiorkor, Laron dwarfs, liver disease, maternal deprivation syndrome, nutritional deficiency, and pituitary tumor.

Usage. Helps identify cause of abnormal growth. Used in conjunction with a growth hormone stimulation test in children with signs of deficient growth hormone. Use in conjunction with a growth hormone sup-pression test in children suspected of having gigantism or adults suspected of having acromegaly; helps evaluate pituitary func-tion. Used to monitor status after removal of a growth hormone–producing tumor. Also used to monitor response to growth hormone therapy.

Description. Insulin-like growth factor-I (IGF-I) is a small polypeptide produced pri-marily in the liver, transported in the plasma, and bound by carrier proteins. Acting via cell

membrane receptors, IGF-I directly stimu-lates growth and proliferation of normal cells and affects glucose metabolism and thus affects growth. Serum levels of IGF-I are regulated both by growth hormone levels and by nutritional status. Increased or decreased growth hormone in the blood-stream causes a directly correlated increase or decrease in the level of IGF-I. Thus this test may be used to confirm growth hormone deficiencies secondary to pituitary abnor-malities. It may also be used when monitor-ing response to growth hormone treatment in growth hormone replacement therapy in adults or in pituitary dwarfism because levels are highest during growth spurts. IGF-I is also used to evaluate the severity of acromegaly.


Preparation1. Tube: Lavender topped.2. Specimens MAY be drawn during

hemodialysis.3. See Client and Family Teaching.


Insulin-like Growth Factor-I (IGF-I)—BloodNorm. Standard reference ranges vary widely. Test result should include reference range.

Male Femaleng/mL SI Units nmol/L ng/mL SI Units nmol/L

Children2 months-5 years 17-248 2.23-32.49 Same as male6-8 years 88-474 11.53-62.09 Same as male9-11 years 110-565 14.41-74.02 117-771 15.33-101.00

Male FemaleTeens/Young Adults12-15 years 202-957 26.46-125.37 261-1096 34.19-143.5816-24 years 182-780 23.84-102.18 Same as maleAdults25-39 years 114-492 14.93-64.45 Same as male40-54 years 90-360 11.79-47.16 Same as male≥55 years 71-290 9.30-37.99 Same as male

I

Intraocular Pressure Measurement 685

Postprocedure Care1. Immediately separate and freeze serum.

The specimen is stable for 30 days.

Client and Family Teaching1. Fast from food and fluids from midnight

before the test.2. Results may not be available for several

days.

Factors That Affect Results1. Results may be falsely elevated if the client

received a radioactive scan within the pre-vious 7 days.

2. During puberty, levels may be 4-5 times higher than adult levels. IGF levels decrease with aging.

3. Norms in pregnant women are higher than those in nonpregnant women.

Other Data1. IGF-I is now produced by recombinant

DNA technology and may be useful in the treatment of acromegaly and certain types of dwarfism.

2. IGF-II is similar in structure to IGF-I and is believed to be an important regulator of embryonic and fetal growth. Its level remains fairly constant after an initial rise in the first year of life.

3. Recent studies of the interrelationship of IGF-I, insulin, and IGF-binding proteins indicate a possible correlation of increased bioavailability of IGF-I with increased risk of colon cancer.

4. The test was formerly known as somato-medin C.

InSureSee Immunochemical Fecal Occult Blood Testing—Stool.

Interferon Gamma Release AssaysSee RD1-Interferon Tests for Tuberculosis—Blood.

International Normalized RatioSee Prothrombin Time and International Normalized Ratio—Blood.

International Sensitivity IndexSee Prothrombin Time and International Normalized Ratio—Blood.

Intraductal UltrasonographySee Pancreas Ultrasonography—Diagnostic.

Intraocular Pressure MeasurementSee Tonometry Test for Glaucoma—Diagnostic.

I

686 Intravascular Coagulation Screen

Intravascular Coagulation ScreenNorm.d-Dimer (fibrin degradation fragment) <1 µg/mL or <100 µg/LFibrinogen Adult 200-400 mg/dL Newborn 125-300 mg/dLFibrin breakdown products <10 µg/mLPlatelet count Adult 150,000-400,000/mm3

Newborn 84,000-478,000/mm3

Activated partial thromboplastin time (APTT) 25-35 secondsProthrombin time Adult 11-15 seconds Newborn 2-35 secondsPremature 3-5 secondsThrombin time 16-23 seconds

Usage. Differentiation of acute dissemi-nated intravascular coagulation (DIC) from chronic DIC.

Description. Intravascular coagulation is a process in which multiple fibrin thrombi with micro infarctions lead to tissue and organ necrosis. This is caused by activation of the clotting mechanism and depletion of clotting factors and platelets with a second-ary fibrinolysis that results in bleeding. In severe situations, the life-threatening condi-tion of DIC can occur. DIC is triggered when the endothelial or other circulating

cells release tissue factor, which activates systemic hemostasis. The systemic activa-tion eventually overcomes natural inhibitor mechanisms, allowing more coagulation to occur. The ongoing coagulation depletes the supply of fibrinogen and platelets, leading to uncontrolled diffuse bleeding. Using a combination of coagulation tests that reveal different aspects of the systemic hemostasis mechanism is necessary to differentiate acute from chronic DIC. The following table lists typical findings for the intravas-cular coagulation screen in acute and chronic DIC.

Test Acute DIC Chronic DICd-Dimer Increased IncreasedFibrinogen Decreased Normal or increasedFibrin breakdown Positive PositivePlatelet count Decreased (or may appear normal if

falling from a baseline high level)Normal or increased

APTT Increased NormalProthrombin time Increased NormalThrombin time Increased IncreasedPeripheral smear Schistocytes present


Preparation1. Tubes: Three red topped, red/gray topped,

or gold topped.

Procedure1. Draw three 5-mL blood samples in the

three tubes.

Postprocedure Care1. Place a pressure dressing on the veni-

puncture site. Monitor closely for bleeding.

Client and Family Teaching1. Clients with disseminated intravascular

coagulation (DIC) may be in acute

Intravenous Cholangiography—Diagnostic 687

I

crisis. Support the family; explain that there may be a need for blood product therapy.

Factors That Affect Results1. Heparin increases clotting time.

Other Data1. DIC is eliminated only by eliminating the

underlying cause. Short-term symptom-atic support includes administration of cryoprecipitate, platelet concentrates, and fresh frozen plasma.

Intravascular UltrasonographySee Coronary Intravascular Ultrasonography—Diagnostic.

Intravenous Cholangiography—DiagnosticNorm. Even filling of the hepatic and biliary ducts. Complete filling of the gallbladder occurs. Negative for stricture or filling defects.

Usage. Alternative to oral cholecystogra-phy when client cannot tolerate oral iodopaque tablets or in clients with active intestinal inflammation; and detection of calculi (or their movement), strictures, or leaking anastomosis or anastomoses in the biliary ductal system.

Description. Intravenous cholangiography involves taking a series of radiographs of the gallbladder and hepatobiliary duct systems over several hours after the intravenous administration of a radiographic contrast medium. The contrast medium is allowed to circulate to the liver through the hepatic artery and empty into the biliary tree. Stric-tures or stones cause defects in the pattern of filling and can be visualized on the radio-graph. Strictures occurring in the hepatobi-liary ducts may be congenital or caused by ductal damage during exploratory or thera-peutic biliary surgery or may be caused by benign or malignant tumor or inflamma-tion. Intravenous cholangiography carries a diagnostic accuracy of 99% for detection of stones in the common bile duct; however, it has NOT been shown to provide incremen-tally superior information than other tests used to evaluate the hepatobiliary system. Gallbladder and biliary system ultrasound, a noninvasive procedure, is the test of choice for evaluating the biliary system and has largely replaced the use of intravenous cholangiography.

See Endoscopic retrograde cholangio- pancreatography—Diagnostic, Gallbladder

and biliary system ultrasonography— Diagnostic.

These three tests that are used more com-monly than intravenous cholangiography.


RisksHypotension, infection, nausea, respiratory failure, tachycardia, vomiting, allergic reac-tion to dye (itching, hives, rash, tight feeling in the throat, shortness of breath, broncho-spasm, anaphylaxis, death), renal toxicity from contrast medium.ContraindicationsRespiratory failure; previous allergy to iodine, shellfish, or radiographic dye; renal insufficiency; during pregnancy (because of radioactive iodine crossing the blood-placental barrier).

Preparation1. A laxative or cathartic may be adminis-

tered 24 hours before the procedure.2. A cleansing or tap-water enema may be

given the morning of the procedure.3. Establish intravenous access.4. Have emergency equipment readily

available.5. See Client and Family Teaching.

Procedure1. The client is positioned supine on the

scanning table.2. A radiographic contrast medium is

injected intravenously or infused by drip and allowed at least 30 minutes to circu-late to the liver and become excreted into the bile ducts. Radiographs of the hepatic and bile ducts are taken at this time.

688 Intravenous Pyelography (IVP, Excretory Urography)—Diagnostic

I

3. 2-3 hours are then allowed to pass to allow the gallbladder to fill with contrast medium. Radiographs may be taken of the gallbladder and biliary system at intervals for up to 8 hours after injection.

Postprocedure Care1. Resume previous diet.2. Assess for allergy to contrast medium for

24 hours.3. Dysuria is not uncommon because the

contrast medium is excreted in the urine.

Client and Family Teaching1. Fast from food and fluids overnight

before the test.2. Morning insulin may be withheld for dia-

betics because the test may take up to 8 hours.

3. A burning or flushing sensation may be experienced when the dye is injected.

4. Bring something to read, if desired, because the test may take several hours.

5. Blockage of the gallbladder can be caused by stones formed from natural bile salts and substances similar in nature to cho-lesterol. A low-fat diet is generally recom-mended for clients with gallbladder disease.

6. In women who are breast-feeding, formula should be substituted for breast milk for 1 or more days after the procedure.

Factors that Affect Results1. Hepatic failure with bilirubin >3.5 mg/dL

(58 mmol/L, SI units) will interfere with gallbladder visualization. The dye must be processed in the liver before it passes into the gallbladder. The test will be canceled for a high bilirubin level.

Other Data1. See also Endoscopic retrograde cholan-

giopancreatography—Diagnostic a test that is used more commonly than intra-venous cholangiography.

Intravenous Pyelography (IVP, Excretory Urography)—DiagnosticNorm. Normal renal pelvis, ureters, and bladder. No obstruction or masses.

Usage. Berger’s disease, glomerulonephritis, hydronephrosis, renal cell cancer, renal failure, renal hypertension, tubular necrosis, and Wilms’ tumor. Examination of the superior ureters during pregnancy as compared with ultrasonography (see Contraindications).

Description. An invasive test that uses con-trast radiopaque dye to assess the ability of the kidneys to excrete dye in the urine. Radiographs are taken after dye injection to visualize the kidneys, ureters, and bladder to assess for obstruction, hematuria, stones, bladder injury, and renal artery occlusion of the renal pelvis. IVP is the first choice for evaluation for kidney stones, if noncontrast computed tomography is not available. IVP is primarily used to examine the upper urinary tract.


throat, shortness of breath, bronchospasm, anaphylaxis, death), renal toxicity from contrast medium, weakness.ContraindicationsDehydration, pregnancy (because of radio-active iodine crossing the blood-placental barrier), previous allergy to iodinated radiographic dye, renal insufficiency.

RisksDysuria, nephrotoxicity, urinary tract infec-tion, vasovagal response, allergic reaction to dye (itching, hives, rash, tight feeling in the

Preparation1. Bowel preparation of orally administered

evacuation preparation 24 hours before the test and evacuation enema 8 hours before test.

2. Assess for high-risk clients: dehydration, elderly, severe diabetes mellitus, renal insufficiency, or multiple myeloma.

3. Have emergency equipment readily available.

4. Just before beginning the procedure, take a “time out” to verify the correct client, procedure, and site.

Procedure1. The client is placed in slight Trendelen-

burg position or supine.2. A venipuncture is performed, and dye is

injected into a vein.

I

IRF 689

3. Serial radiographs are taken periodically for the next 30 minutes.

Postprocedure Care1. The client should drink at least three

8-ounce glasses of liquid to flush the kidneys of the dye (when not contraindicated).

2. Assess for signs of allergic reaction to the dye (listed under Risks) for 24 hours.

Client and Family Teaching1. It is normal to feel flushed and warm

and to notice a salty taste soon after the dye is injected. This will last only a few moments.

2. Stress the importance of drinking water after the test to flush dye from the body, prevent osmotic diuresis from the dye, and protect the kidneys.

3. In women who are breast-feeding, formula should be substituted for breast milk for 1 or more days after the procedure.

Factors That Affect Results1. Poor bowel evacuation or poor renal per-

fusion will decrease the uptake of dye, leading to poor radiograph quality.

Other Data1. Dosages of radiation range from 1047 to

1465 mR (milliroentgens).2. The test Magnetic resonance urography—

Diagnostic, although much more costly, is superior to renal ultrasonography in identifying pathology for clients with kidneys that do not opacify (such as those with renal transplants) during excretory urography.

Intrinsic Factor Antibody—BloodNorm. Negative; none detected.

Positive. Graves’ disease, insulin-dependent diabetes, megaloblastic anemia, and perni-cious anemia.

Description. Intrinsic factor is produced by the parietal cells of the gastric mucosa and is required for the effective absorption of vitamin B12. In some diseases, antibodies that bind the cobalamin-intrinsic factor complex are produced and prevent the complex from binding to receptors in the ileum.



gold topped.2. Do not collect a sample if vitamin B12 was

injected or ingested by client within 48 hours before the test.



Client and Family Teaching1. If the test results show the presence of

antibodies and a positive diagnosis is made of pernicious anemia, the client requires regular injections of vitamin B12 because of the body’s inability to produce the intrinsic factor secreted by the parietal cells in the stomach lining.

Factors That Affect Results1. Reject if the client had a radioactive scan

within 7 days before the test.

Other Data1. Causes of vitamin B12 deficiency include

pancreatic insufficiency, parasitic infesta-tions of the small intestine, regional enteritis, malnutrition, or transcobalamin protein abnormalities.

IRFSee Reticulocyte Count—Blood.

690 Iron (Fe)—Serum

I

Iron (Fe)—SerumNorm.

SI UnitsAdult female 40-150 µg/dL 7.2-26.9 µmol/LAdult male 50-160 µg/dL 8.9-28.7 µmol/LNewborn 100-250 µg/dL 17.9-44.8 µmol/LInfant 40-100 µg/dL 7.2-17.9 µmol/LChild 50-120 µg/dL 8.9-21.5 µmol/LPanic level >300 µg/dL >54.05 µmol/L

Description. Iron is an inorganic ion, found mostly in hemoglobin, that acts as a carrier of oxygen from the lungs to the tissues and indirectly aids in the return of carbon dioxide to the lungs. Although the primary source of body iron is food, only a small portion of that consumed from the diet is absorbed. Iron is stored in the liver and reticuloendothelial tissue in the form of ferritin and hemosiderin and is released from storage as needed to meet the body’s demands. Although iron levels are assumed to be highest in the morning because of a diurnal variation, studies have not shown that restricting specimen collection to the morning improves the reliability of the result. Significant toxicity can occur with ingestions of over 20 mg/kg of iron.



gold topped.2. Screen client for use of herbal medicines

or natural remedies.3. Document the date of the last

blood transfusion on the laboratory requisition.

4. Do NOT draw specimens during hemodialysis.

Procedure1. If using Vacutainer and venipuncture for

multiple samples, draw this sample first to avoid mixing heparin with the sample. Draw a 7-mL blood sample.


Client and Family Teaching1. The basic role of iron in hemoglobin for-

mation is to allow blood to efficiently

Panic Level Symptoms and TreatmentSymptoms1. 0-6 hours after ingestion: vomiting and

diarrhea, abdominal pain, gastrointesti-nal bleeding/bloody diarrhea.

2. 6-24 hours after ingestion: may be asymptomatic.

3. 12-48 hours after ingestion: metabolic acidosis, shock, coma, seizures, purpura, renal failure.

4. Toxic/panic symptoms (risk with inges-tion of over 60 mg/kg): shock and coma may be the first symptoms seen.

Treatment1. Support airway, breathing, and

circulation.2. Gastric lavage is useful only if started

within 1 hour of ingestion.3. Perform whole bowel irrigation with

polyethylene glycol (used with caution).4. Induce chelation with intravenous defer-

oxamine. Start immediately, without waiting for other test results, if serious ingestion is verified.

5. Hemodialysis and peritoneal dialysis help remove ferrioxamine in clients who are anuric.

Increased. Acute hepatitis, aplastic anemia, blood transfusion, hemochromatosis, hemo-lytic anemia, hepatitis, lead poisoning, nephritis, pernicious anemia, polycythemia, sideroblastic anemia, thalassemia, and vitamin B6 deficiency. Drugs include alcohol (wine, ethanol).

Decreased. Blood loss, burns, carcinoma, gastrectomy, infection, iron deficiency anemia, kwashiorkor, malabsorption, nephro-sis, postoperative state, pregnancy, rheuma-toid arthritis, schizophrenia (chronic), tetralogy of Fallot, and uremia. Drugs include metformin.

Iron (Fe) and Total Iron-Binding Capacity (TIBC)/Transferrin—Serum 691

I

carry oxygen to the tissues. Foods rich in iron include red meats and some green, leafy vegetables.

Factors That Affect Results1. Hemolysis of the specimens invalidates

the results.2. Vitamin B12 ingested within 48 hours may

increase the results.3. Herbs that interfere with iron absorption

include St. John’s wort and saw palmetto, which contain tannic acids.

4. Iron levels in blood do not correlate well with the amount of iron ingestion. Therefore treatment should be based on

symptoms and on what is known about the amount of iron ingested.

Other Data1. Adenocarcinoma of the gastrointestinal

tract may be detected by iron deficiency.2. Increased serum iron concentrations of

300-500 mg/dL (53.7-89.6 mmol/L, SI units) can be the result of one ingested iron tablet.

3. Increased ferritin levels frequently accom-pany neoplastic activity.

4. See also Ferritin—Serum; Iron and total iron-binding capacity/transferrin—Serum; Soluble transferrin receptor assay—Serum.

Iron (Fe) and Total Iron-Binding Capacity (TIBC)/Transferrin—SerumNorm.

SI UnitsAdult female 40-150 µg/dL 7.2-26.9 µmol/LAdult male 50-160 µg/dL 8.9-28.7 µmol/LNewborn 100-250 µg/dL 17.9-44.8 µmol/LInfant 40-100 µg/dL 7.2-17.9 µmol/LChild 50-120 µg/dL 8.9-21.5 µmol/LTIBCAdult 250-400 µg/dL 44.8-71.6 µmol/LInfant 100-400 µg/dL 17.9-71.6 µmol/LTransferrin saturation 20% to 45%Adult 200-400 mg/dL 2-4.0 g/LMaternal 305 mg/dL 3.0 g/L(Term)Fetal 190 mg/dL 1.9 g/LNewborn 130-275 mg/dL 1.3-2.8 g/L

Increased TIBC. Hepatitis, microcytic anemia, and pregnancy. Drugs include iron salts and oral contraceptives.

Decreased TIBC. Cirrhosis, dysmenorrhea, hemochromatosis, hemorrhage, hepatitis, hypothyroidism, kwashiorkor, microcytic anemia, myocardial infarction, neoplasm, nephrosis, pernicious anemia, thalassemia, and uremia. Drugs include ACTH, asparagi-nase, chloramphenicol, corticotropin, corti-sone, dextran, steroids, and testosterone.

Description. This test differentiates anemia secondary to iron deficiency from other dis-eases associated with variations in cellular oxidation. Iron is an element necessary for many body processes, including the

transport of oxygen to the tissues and for oxygen-carrying chromoproteins, hemoglo-bin, myoglobin, and enzymes such as xan-thine oxidase and peroxidase. Transferrin is a plasma iron-transport protein, also called siderophilin, formed in the liver that has a half-life of 7-10 days. Transferrin is capable of binding more than its own weight in iron (that is, 1 g of transferrin can carry 1.43 g of iron). In normal clients, iron saturation of transferrin is between 20% and 45%. Trans-ferrin saturation by iron demonstrates a diurnal pattern, with a morning peak and an early evening trough. The formula for trans-ferrin saturation by iron is:

( )Serum iron/TIBCTransferrin saturation

×=

100

I

692 Iron Stain, Bone Marrow

TIBC is the maximum amount of iron that can be bound to transferrin. It is useful in distinguishing anemia (increased value) from chronic inflammatory disorders (normal value). In this test, iron is added to the client’s serum until all transferrin-binding sites are bound with iron. Then the excess iron is removed, and the total amount of remaining (bound) iron is measured, giving an assessment of the ability of the individual’s transferrin to bind iron.



gold topped; and 20-gauge or larger needle.

2. Document the date of the last blood transfusion on the requisition.

3. See Client and Family Teaching.

Procedure1. Draw a 7-mL blood sample, without

hemolysis.


Client and Family Teaching1. Fast 12 hours before sampling. Water is

permitted.2. If the results indicate a low level of iron,

eat foods rich in iron such as organ meats, eggs, and dried fruits.

Factors That Affect Results1. Inflammatory states may decrease results

below normal.2. Hemolysis may cause falsely elevated iron

values.

Other Data1. A decrease in iron and an increase in

TIBC are found in microcytic anemia.2. Serum transferrin may be calculated from

TIBC using the following formula:

0 8 43. × −TIBC

3. See also Soluble transferrin receptor assay—Serum; Transferrin—Serum.

Iron Stain, Bone MarrowSee Bone Marrow Aspiration Analysis—Specimen.

ISISee Prothrombin Time and International Normalized Ratio—Blood.

Isopropyl AlcoholSee Toxicology, Volatiles Group by GLC—Blood or Urine.

IVPSee Intravenous Pyelography—Diagnostic.

Ivy Bleeding TimeSee Aspirin Tolerance Test—Diagnostic; Bleeding Time, Ivy—Blood.

medicina interna 2

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