Packed cell volume count (Hematocrit) Enas Sabah MSc. Human Physiology

P.C.V is the volume of the blood made only by the blood cells per 100 ml of blood. The two main parts of blood are the plasma (which constitute on average about 55% of the blood volume) and the blood cells (which constitute about the 45% of the blood volume).

Red Blood Cells (Erythrocytes) Normal red blood cells, are biconcave discs In healthy men, the average number of red blood cells per cubic millimeter is 5,200,000 (±300,000); in women, it is 4,700,000 (±300,000).

The red blood cells are the most abundant cell in the blood and the value of the P.C.V reflects the volume of the red blood cells.

Procedure: Clean the thumb with alcohol soaked cotton and puncture it. Allow the blood to enter the capillary tube by capillary attraction leaving at least 15 mm unfilled (or fill about 80% of the tube with blood). Seal one end of the capillary tube by sealing clay.

4. Spin the capillary tube in a micro-centrifuge for 5 minutes at about 10000 RPM. 5. Read the value of the P.C.V by the Hematocrit reader.   Normal range of P.C.V for adult male is 47 ± 7% and for adult female 42 ± 5%. Increase in the volume of P.C.V above the reference range is termed as polycythemia while decrease in the volume below normal is called anemia.

If there is rise or fall in the percentage of RBCs in relation to the volume of plasma, it indicates presence of health problems. Hematocrit (PCV) value Increase in the following conditions: Dehydration Burn Injury Polycythemia Vera  High Altitude Conditions associated with hypoxia

Hematocrit value decrease in the following conditions: Pregnancy  Renal failure Bone marrow failure Hemolytic anemia chemotherapy