PACKED CELL VOLUME ?USES,METHODS OF COLLECTION,ITS SIGNIFICANCE AND REFERENCE RANGES
PACKED CELL VOLUME
- Its also called hematocrit
- Volume occupied by red cell when sample of anticoagulated blood is centrifuged
- It indicates relative proportion of red cell to plasma
- It is expressed as percentage of original volume of blood or as decimal fraction
USES:
- Detection of presence /absence of anemia or polycythemia
- Estimation of red cell indices
(mean cell volume +mean corpuscular Hb concentration)
- Checking accuracy of Hb value
(Hb in g/dl *3=PCV)
METHODS:
- Two methods for estimation Macro(WINTROBE),MICRO(MICROHEMATOCRIT)
- Micro method is preferred :
Rapid
Convenient
Small amount of blood
- After centrifugation of anticoagulated three zones can be seen above downward:
- Plasma
- Buffy coat
- Packed cell
- Smear from puffy coat for demonstration of lupus erythematosus, malaria parasite and immature cells
- plasma IS usually Straw coloured
- If colorless-IRON DEFICIENCY
- PINK-HEMOGLOBINEMIA
- YELLOW-JAUNDICE
- MILKY-HYPERTRIGLYCERIDEMIA
SIGNIFICANCE:
- In anemia :Packed cell volume below lower level
- Pack cell volume increases in shock, burn and polycythemia
REFERANCE RANGE:
- Adult male:40-50%
- Adult female-38-45%
- Adult female (pregnant)-36-42%
- Newborn-44-60%
Precaution:
- Excess squeezing of finger -dilute sample-hematocrit
- Decreased hematocrit if clot are present
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