(1) The ratio of blood volume that is occupied by red blood cells, usually expressed as a percentage of the total blood volume.
(2) The instrument used to determine the relative amounts of corpuscles and plasma in the blood.
An average (normal) value in men is 46% and in women is 38%.
Word origin: the term "hematocrit" was coined in 1903. Its roots stem from the Greek words hemat - blood, and krites, judge - meaning to gauge or judge the blood.
Abbreviation: Ht, HCT.
Synonym: packed cell volume (PCV), erythrocyte volume fraction (EVF).