WHAT IS PACKED CELL VOLUME (PCV) OR HEMATOCRIT? USES AND METHODS FOR ESTIMATION OF PACKED CELL VOLUME (PCV)
Packed cell volume (PCV) is the volume occupied by the red cells when a sample of anticoagulated blood is centrifuged. It indicates relative proportion of red cells to plasma. PCV is also called as hematocrit or erythrocyte volume fraction. It is expressed either as a percentage of original volume of blood or as a decimal fraction.
USES OF PCV
- Detection of presence or absence of anemia or polycythemia
- Estimation of red cell indices (mean cell volume and mean corpuscular hemoglobin concentration)
- Checking accuracy of hemoglobin value (Hemoglobin in grams/dl × 3 = PCV).
There are two methods for estimation of PCV: macro method (Wintrobe method) and micro method (microhematocrit method). Micro method is preferred because it is rapid, convenient, requires only a small amount of blood, capillary blood from skin puncture can be used, and a large number of samples can be tested at one time.
This method is also more accurate as plasma trapping in red cell column is less.