Hematocrit

<B>Hematocrit:</B> The proportion of the blood that consists of packed red blood cells.

The hematocrit is expressed as a percentage by volume.

The red cells are packed by centrifugation.

For example, an hematocrit of 25% means that there are 25 milliliters of red blood cells in 100 milliliters of blood.

The red cells make up a quarter of the blood.

The normal ranges for the hematocrit are dependant on the age and, after adolescence, the sex of the individual.

The normal ranges for the hematocrit are: > >Newborns: 55-68% >One (1) week of age: 47-65% >One (1) month of age: 37-49% >Three (3) months of age: 30-36% >One (1) year of age: 29-41% >Ten (10) years of age: 36-40% >Adult males: 42-54% >Adult women: 38-46%</LI></UL> These values may vary slightly between laboratories.

The term 'hematocrit' was coined in 1903 and comes from the Greek roots hemat-, blood + krites, judge = to judge or gauge the blood.

The abbreviation for hematocrit is hct.

In medical slang the hematocrit is called the crit.