Card Set Information

2014-03-08 03:59:59
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  1. Describe the Hematocrit procedure in detail
    • Fill capillary tube 1/2 to 2/3 full with whole blood to be tested
    • Place fingertip over one end of the tube and wipe of excess blood from the exterior of the tube
    • Remove finger from the end of the tube and press one end of tube into clay or sealant
    • **note: Sealant should fill at least 1/4 inch of the end of the tube
    • **note: fill duplicate tubes for each specimen tested (for verification)
    • Place tubes opposite each other in the grooves in the hematocrit centrifuge with SEALED ENDS TOWARD THE OUTSIDE
    • Screw down the internal cover
    • Centrifuge specimens for 5 minutes at 14,500 rpm
    • Open centrifuge after it comes to a complete stop
    • Using a microhematocrit reader determine RBC percentage (make sure clay/red cell interface is placed at 0% and the plasma meniscus is placed at 100%)
    • **note: duplicates should match within 1%
  2. What are the normal hematocrit values?
    • Newborn: 53-66%
    • Adult male: 42-52%
    • Adult female: 37-47%
  3. Describe the hemoglobin determination procedure in detail
    • Addition of lysing agent results in free hgb
    • Addition of potassium ferricyanide forms methemoglobin (reduced hgb)
    • Addition of potassium cyanide forms cyanmethemoglobin (colored)
    • Cyanmethemoglobin is read @ 540nm in spectrophotometer (after serial dilution)
  4. What are the normal hemoglobin values?
    • Newborn: 17-23 g/dL
    • Adult male: 14-18 g/dL
    • Adult female: 12-16 g/dL
  5. What are the 3 RBC indices (names) and what do the indicate?
    • Mean corpuscular volume (MCV): average size of RBC
    • Mean corpuscular hemoglobin (MCH): average amount of hgb per RBC
    • Mean corpuscular hemogblon concentration (MCHC): average concentration of hemoglobin per cell (related to color)
    • Red Blood Cell Distribution Width (RDW): indicates the amount that RBCs vary in size
    • Mean Platelet Volume (MPV): average size of platelet
  6. How do you derive MCV and what are its associated values?
    • Mean corpuscular volume
    • Normocytic: 80-100fL (femtoliters)
    • Microcytic: <80fL
    • Macrocytic: >100fL
  7. How do you derive MCH and what are its associated values?
    • Mean corpuscular hemoglobin
    • Normal MCH: 27-31pg (picograms)
  8. How do you derive MCHC and what are its associated values?
    • Mean corpuscular hemoglobin concentration
    • Normochromic: 32-36%
    • Hypochromic: <32%
  9. How do you derive RDW and what are its associated values?
    • Red Blood Cell Distribution Width
    • Normal value: 11.5-14.5%
    • Elevated RDW indicates anisocytosis
  10. How do you derive MPV and what are its associated values?
    • Mean Platelet Volume
    • *performed by machine
    • Normal value: 7.4-10.4fL
    • Value increased in idiopathic (unknown) thrombocytopenic purpura (ITP)