(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 for HCT 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).