he·​mat·​o·​crit | \ hi-ˈma-tə-krət How to pronounce hematocrit (audio) , -ˌkrit \

Definition of hematocrit

: 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

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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 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

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'hematocrit.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of hematocrit

circa 1903, in the meaning defined above

History and Etymology for hematocrit

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

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The first known use of hematocrit was circa 1903

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Cite this Entry

“Hematocrit.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/hematocrit. Accessed 27 Jan. 2022.

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More Definitions for hematocrit


variants: or chiefly British haematocrit \ hi-​ˈmat-​ə-​krət, -​ˌkrit How to pronounce hematocrit (audio) \

Medical Definition of hematocrit

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

More from Merriam-Webster on hematocrit

Britannica.com: Encyclopedia article about hematocrit


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