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:

  1. Plasma
  2. Buffy coat
  3. 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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