hematocrit

noun

he·​mat·​o·​crit hi-ˈma-tə-krət  -ˌkrit 

: the ratio of the volume of red blood cells to the total volume of blood as determined by separation of red blood cells from the plasma usually by centrifugation

Did you know?

Our blood is mostly made up of four components: plasma, red blood cells, white blood cells, and colorless blood cells called platelets. An instrument called a hematocrit (because it "judges" the blood) is used to separate a sample of blood into its components. The normal hematocrit for men is about 48%, for women about 38%. An abnormal proportion of red blood cells, either too many or too few, is a good early indicator of many diseases. So when you give blood as part of a physical exam, your hematocrit is one of the findings your doctor will often check.

Examples of hematocrit in a Sentence

Recent Examples on the Web

Blood samples showed that their hematocrit levels—a measure of red blood cells, which carry oxygen—had also increased. —Elizabeth Preston, Discover Magazine, 27 Jan. 2015

Lundby’s hypothesis is based on the idea that your kidneys are constantly monitoring hematocrit, trying to keep it in a normal range. —Alex Hutchinson, Outside Online, 1 July 2020

However, if the liquid portion is greatly increased through training, the proportion that makes up the hematocrit will decrease accordingly, falsely suggesting anemia. —Bryant Stamford, The Courier-Journal, 28 Apr. 2022

If your total blood is made up of 45 percent red blood cells by volume, your hematocrit is 45. —Alex Hutchinson, Outside Online, 1 July 2020

If heat training causes your plasma volume to increase, that will lower your hematocrit. —Alex Hutchinson, Outside Online, 1 July 2020

Typically, the ratio of solids in the blood (RBCs, white blood cells and platelets called the hematocrit) to the liquid portion is approximately 50-50. —Bryant Stamford, The Courier-Journal, 28 Apr. 2022

His complete blood count, to include his white blood cell count, his hemoglobin, hematocrit, and platelet count were all normal. —Jamie Ducharme, Time, 18 Jan. 2018

Word History

Etymology

International Scientific Vocabulary hemat- + Greek kritēs judge, from krinein to judge — more at certain

First Known Use

circa 1903, in the meaning defined above

Medical Definition

hematocrit

noun

he·​mat·​o·​crit

variants or chiefly British haematocrit

hi-ˈmat-ə-krət, -ˌkrit 

1

: an instrument for determining usually by centrifugation the relative amounts of plasma and corpuscles in blood

2

: the percent of the volume of whole blood that is composed of red blood cells as determined by separation of red blood cells from the plasma usually by centrifugation

a hematocrit ranging from 42% to 52% in males and 35% to 47% in females is typically considered normal

called also packed cell volume