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  • CHAPTER 1

    Blind folio 1

    Hematology Tests

    Hematology is the study of blood, blood diseases, and organs that form blood. Hematology clinical laboratory tests are used to examine blood and blood components to determine if they are within normal limits. Values outside the normal limits might be signs of a disease.

    Hematology tests count the number of white and red blood cells and platelets. In addition, these tests measure the time necessary for blood to clot and the capability of blood to carry oxygen throughout the body. Hematology tests also determine infl ammation and infection in the patient and the type of infection.

    In this chapter youll learn how to collect a blood specimen and learn about commonly performed hematology tests.

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  • 2 Nursing Lab and Diagnostic Tests Demystifi ed

    Learning Objectives1 How to Collect Blood Specimen from a Vein

    2 How to Collect Blood Specimen from a Heel Stick

    3 How to Collect Blood Specimen from a Finger Stick

    4 Blood Type Test

    5 Partial Thromboplastin Time (PTT)

    6 Total Serum Protein

    7 Blood Alcohol

    8 Lead

    9 Serum Osmolality

    10 Uric Acid in Blood

    11 C-Reactive Protein (CRP)

    12 Complete Blood Count (CBC)

    13 Chemistry Screen

    14 Vitamin B12

    15 Cold Agglutinins

    16 Toxicology Tests (Tox Screen)

    17 Folic Acid

    18 Gastrin

    19 Ferritin

    20 Lactic Acid

    21 Prothrombin Time

    22 Reticulocyte Count

    23 Schilling Test

    24 Sedimentation Rate (SR)

    25 Iron (Fe)

    26 Serum Protein Electrophoresis (SPE)

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  • CHAPTER 1 Hematology Tests 3

    Healthcare facilities provide training for collection of blood specimen. Here are the basic steps that are necessary to collect a blood sample.

    1. Wrap a tourniquet around the patients upper arm to stop blood fl ow, making veins easier to identify.

    2. Clean the puncture site with alcohol.

    3. Insert the needle into the vein with the bevel up.

    4. Attach the appropriate test tube to the needle. Allow the blood to fi ll the test tube.

    5. Remove the tourniquet to restore blood fl ow.

    6. Place a gauze pad over the site while withdrawing the needle.

    7. Apply fi rm pressure to the site until bleeding has stopped.

    Key WordsABOAgglutininsAlbuminAntidiuretic hormone (ADH)AntigensBlood group antigens CoumadinC-reactive proteinErythrocyte indicesFerritinFibrinogenGastrinGlobulinHeparinIntrinsic factor

    How to Collect Blood Specimenfrom a Vein 1

    Lactic acidOsmolalityParietal cellsPartial thromboplastin time (PTT)Phlebitis Prothrombin time (PT)PurineReticulocyteRh antigenRh factorRouleaux formationThromboplastinToxinTransferrin protein

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  • 4 Nursing Lab and Diagnostic Tests Demystifi ed

    TEACH THE PATIENT Explain that

    The tourniquet may feel tight.

    The patient may feel a pinch or nothing at all when the needle is inserted into the vein.

    There might be a small bruise at the site. Keeping pressure on the site reduces the chance of bruising.

    Taking anticoagulants (aspirin, Coumadin) may require keeping pressure on the site for more than 10 minutes to stop the bleeding.

    The vein may become swollen after the test (phlebitis). The patient should call their healthcare provider and apply a warm compress to reduce the swelling.

    How to Collect Blood Specimen froma Heel Stick 2

    Several drops of blood are collected from the heel of a baby.

    1. Clean the heel with alcohol.

    2. Puncture the heel with a small sterile lancer.

    3. Collect several drops of blood in a small test tube.

    4. Place a gauze pad over the site.

    5. Maintain pressure until bleeding stops.

    6. Apply a small bandage.

    TEACH THE PARENT Explain

    That the patient may feel a pinch or nothing at all when the lancer punctures the skin.

    There will be a bandage on the site for a short-time period.

    That a small bruise might appear at the site.

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  • CHAPTER 1 Hematology Tests 5

    Several drops of blood are collected from the fi nger.

    1. Clean the fi nger with alcohol.

    2. Puncture the fi nger with a small sterile lancer.

    3. Collect several drops in a small test tube.

    4. Place a gauze pad over the site.

    5. Maintain pressure until bleeding stops.

    6. Apply a small bandage.

    TEACH THE PATIENT Explain

    That the patient may feel a pinch or nothing at all when the lancer punctures the skin.

    There will be a bandage on the site for a short-time period.

    A small bruise might appear at the site.

    Blood is identifi ed by an antigen on the surface of red blood cells. Major types of these antigens are blood group antigens and Rh antigen. There are four types of blood group antigens that are determined by performing the ABO test.

    Type A: Has the A antigen and antibodies in plasma against B antigen.

    Type B: Has the B antigen and antibodies in plasma against A antigen.

    Type O: Has neither the A antigen nor the B antigen and antibodies in plasma against A antigen and B antigen.

    Type AB: Has both the A antigen and the B antigen and no antibodies in plasma against A antigen and B antigen.

    Red blood cells may have the Rh antigen attached to them, sometimes called the Rh factor, and is determined by the Rh test.

    How to Collect Blood Specimenfrom a Finger Stick 3

    Blood Type Test 4

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  • 6 Nursing Lab and Diagnostic Tests Demystifi ed

    Rh positive (+): The Rh antigen is presented on the red blood cells.

    Rh negative (): The Rh antigen is not presented on the red blood cells.

    A patients blood type is described as a combination of blood group antigen and Rh antigen by using the blood type letter(s) followed by a plus (+) or minus () sign, indicating if the Rh antigen is present. For example, type A means that the patient has the A antigen but doesnt have the Rh antigen attached to the red blood cells.

    HINTHINT

    The test will also examine minor antigens that, attached to red blood cells, can cause an adverse blood transfusion reaction.

    WHAT IS BEING MEASURED? Blood group antigens on red blood cells

    Rh antigens on red blood cells

    HOW IS THE TEST PERFORMED?See How to Collect Blood Specimen from a Vein.

    RATIONALE FOR THE TEST Assess

    Blood compatibility for a blood transfusion and organ transplant

    If a pregnant woman is Rh positive or negative

    NURSING IMPLICATIONS Assess the patient for conditions that might affect the test results.

    The patient has taken methyldopa, levodopa, or cephalexin. These medications can cause a false Rh positive test result.

    Recent X-ray with contrast.

    Bone marrow transplant.

    A blood transfusion in the previous 3 months.

    Has or has had cancer or leukemia.

    HINT

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  • CHAPTER 1 Hematology Tests 7

    UNDERSTANDING THE RESULTS The result is available in an hour.

    The following chart lists blood type compatibility between a recipient (the patient) and a donor.

    Recipient Donor

    AA+

    BB+

    ABAB+

    OO+

    A OA A+ O O+B OB B+ O O+AB OAB AB+ A A+ B B+ O O+OO O+

    HINTHINT

    It was once thought that type O negative is the universal blood donor, meaning that a patient can receive O negative blood regardless of the patients blood type. Type AB positive is the universal recipient. It is now understood that these blood types contain antibodies that can cause a transfusion reaction. Before any transfusion, a sample of the recipients blood is cross-matched (mixed) with the donors blood in the laboratory to determine compatibility.

    TEACH THE PATIENT No special preparation is needed for the test.

    Explain how the test is performed.

    Explain the conditions that can negatively affect the test results.

    When bleeding occurs, 12 blood clotting factors cause the blood to coagulate to stop the bleeding. Coagulation of blood is affected by blood clotting factors, which can be absent and of decreased or increased levels, or by changes in the way blood clotting factors

    Blood Transfusion Compatibility Chart

    Partial Thromboplastin Time 5

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  • 8 Nursing Lab and Diagnostic Tests Demystifi ed

    function. In addition, clotting inhibitors can reduce the effectiveness of clotting factors. The partial thromboplastin time (PTT) test measures the clotting time of blood.

    HINTHINT

    Another blood clotting test is prothrombin time (PT). The heparin neutralization assay is performed to determine if substances other than heparin cause an increase in PTT.

    WHAT IS BEING MEASURED? The time necessary for blood to clot

    HOW IS THE TEST PERFORMED? The test may be performed frequently for patients who experience a

    clotting or bleeding problem. The test is also performed before invasive procedures and before surgery.

    The test is performed frequently for patients taking heparin until th

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