Hematocrit

Hematocrit is the proportion of erythrocytes in the total volume of blood. It is determined by centrifugation of non-clotting blood. During centrifugation, the erythrocytes are separated from the plasma. The white, opaque layer just above the erythrocytes, sometimes referred to as the buffy coat, is made up of platelets and leukocytes and makes up about 1% of the total blood volume. The resulting hematocrit value is given in % or in ratio numbers.

When collecting blood for hematocrit, the anticoagulant must not affect the final volume of the sample!

Physiological values of hematocrit

 * men: 44±5 % (0,44±0,05)
 * women: 39±4 % (0,39±0,04)

The hematocrit value decreases, for example, when the number of erythrocytes decreases, their volume decreases or when the plasma volume increases.

Related articles

 * Erytrocytes
 * Hamburger effect