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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 rpmOpen 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%
What are the normal hematocrit values?
- Newborn: 53-66%
- Adult male: 42-52%
- Adult female: 37-47%
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)
What are the normal hemoglobin values?
- Newborn: 17-23 g/dL
- Adult male: 14-18 g/dL
- Adult female: 12-16 g/dL
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
How do you derive MCV and what are its associated values?
- Mean corpuscular volume
- Normocytic: 80-100fL (femtoliters)
- Microcytic: <80fL
- Macrocytic: >100fL
How do you derive MCH and what are its associated values?
- Mean corpuscular hemoglobin
- Normal MCH: 27-31pg (picograms)
How do you derive MCHC and what are its associated values?
- Mean corpuscular hemoglobin concentration
- Normochromic: 32-36%
- Hypochromic: <32%
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
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)
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