Download - Copyright ©2012 Delmar, Cengage Learning. All rights reserved. Chapter 45 Diagnostic Testing
Copyright ©2012 Delmar, Cengage Learning. All rights reserved.
Chapter 45
Diagnostic Testing
Copyright ©2012 Delmar, Cengage Learning. All rights reserved.
Quality Control
• Quality control and assurance are important to the integrity of test results
• Perform controls:– At the beginning of each day– When opening a new bottle of reagent strips
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Quality Control
• Document the following in the log book:– Date– Patient’s name– Test performed– Results of test– Your initials– Kit, reagent strip, lot numbers, expiration dates– Quality control results
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Hematology Testing
• Hemoglobin and hematocrit– Screening tests that require a small amount of
blood– Usually obtained through a capillary puncture– Hematocrit may use either capillary blood or
venous blood
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Hemoglobin
• Hemoglobin is essential to oxygen circulation in the body
• Normal ranges– Males: 14-18 g/dL– Females: 12-16 g/dL
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Hematocrit
• Screens for anemia• Normal ranges
– Males: 40-54%– Females: 37-47%
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Complete Blood Count
• Common test ordered in provider’s office, which measures many values
Total red blood cell count Total granulocyte count
Total white blood cell count Total lymphocyte and monocyte count
Total platelet count Percentage of granulocytes
Hemoglobin Percentage of lymphocytes and monocytes
Hematocrit Red blood cell indices
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WBC Differential
• Performed on 100 white blood cells– Numbers of neutrophils, eosinophils, basophils,
monocytes, and lymphocytes counted• Physicians review for abnormalities of the red
blood cells• MAs do not perform these counts, but should
be familiar with the reports
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ESR
• Rate at which red blood cells settle in a calibrated tube within a given time
• Determines how much inflammation is occurring in response to another disease condition
• Two methods– Westergren– Wintrobe
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Glucose Testing
• Capillary blood samples usually used• Handheld meter with reagent strips• Perform quality controls
– At the beginning of each day– When opening a new package of reagent strips– Log results prior to reporting patient results
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Glucose Tolerance Testing
• Performed when patient has consistently high fasting blood sugar– To help provider make a diagnosis of diabetes
mellitus or hypoglycemia• Determines the patient’s ability to metabolize
a glucose load over a prescribed amount of time
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Hemoglobin A1C
• Modified form of hemoglobin• Helps determine how the diabetic patient has
been controlling blood sugar over 2-3 months• Often ordered with random blood sugar level
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Immunology
• The study of the body’s ability to prevent and fight off infection
• Immunoassays are diagnostic tests that measure the amount of antigens and antibodies present relative to an illness
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Mononucleosis Testing
• Illness causes by the Epstein Barr virus– Symptoms similar to the flu– Extremely contagious– Most common in individuals 10-25 years old
• Immunoassay detects the presence or absence of the antibodies to EBV
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Allergy Testing
• This type of testing involves introducing an antigen directly into the patient’s skin to induce a reaction
• If the reaction is negative (normal), there will be no change in the skin
• If the reaction is positive, a wheal will develop on the skin
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Allergy Testing
• Skin prick tests– Allergen is applied directly to patient’s skin and
scratched or “pricked” into the epidermis• Intradermal injections
– Allergen is injected between the epidermis and dermis
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Allergy Testing
• Skin patch tests– Allergen-soaked pad is applied to the surface of
the skin for 24-72 hours• RAST
– Determines the presence of immunoglobulins– Test given when individuals cannot tolerate skin
tests
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Allergy Testing
• Nasal smears– Aids in the diagnosis of allergies– Smear done with nasal secretions– Provider observes the eosinophil count
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HIV Testing
• Standard screening tests are enzyme immunoassays
• May have to draw blood for this screening• Follow policy and procedure for collection as
well as standard precautions
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PKU Testing
• Screening test done on infants using capillary blood– Drops of blood are soaked through outlined circles
on PKU testing card and attached to requisition– The card and form are send to state health
department for processing• Required in all states and Canada
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Testing Outside the POL
• Series of tests ordered are done as panels or profiles– Panels are less expensive than individual tests
• MA responsibilities– Prepare specimen for sending– Screen test results as they are returned to
provider’s office– Immediately follow-up panic values