hematocrit

/hi mat"euh krit/, n.
1. a centrifuge for separating the cells of the blood from the plasma.
2. Also called hematocrit value. the ratio of the volume of red blood cells to a given volume of blood so centrifuged, expressed as a percentage.
[1890-95; HEMATO- + -crit < Gk krités judge]

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▪ medical analysis
also spelled  haematocrit 

      diagnostic procedure for the analysis of blood. The name is also used for the apparatus in which this procedure is performed and for the results of the analysis. In the procedure, an anticoagulant is added to a blood sample held in a calibrated tube. The tube is allowed to stand for one hour, after which the sedimentation rate (how rapidly blood cells settle out from plasma) is determined. Most acute generalized infections and some local infections raise the rate of sedimentation. A raised sedimentation rate may be among the first signs of an otherwise hidden disease.

      In the second phase of the procedure, the tube is centrifuged so that its contents separate into three layers—packed red blood cells (erythrocytes (erythrocyte)) at the bottom, a reddish gray layer of white blood cells (leukocytes (leukocyte)) and platelets (platelet) in the middle, and plasma at the top. The hematocrit is expressed as the percentage of the total blood volume occupied by the packed red blood cells. The depths of these layers are indicative of health or disease: the red blood cell layer is abnormally thick in the disease polycythemia and too thin in iron-deficiency anemia (iron deficiency anemia); white blood cells are too abundant in leukemia; and plasma is deep yellow in jaundice (often caused by liver disease). The hematocrit is among the most commonly used of all laboratory diagnostic procedures.

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Universalium. 2010.

Look at other dictionaries:

  • Hematocrit — Intervention Blood components MeSH …   Wikipedia

  • hematocrit — HEMATOCRÍT, hematocrite, s.n. Aparat care permite separarea prin centrifugare a elementelor celulare din plasmă, pentru stabilirea gradului de diluţie sau de concentrare a sângelui; hematoglobinometru. – Din fr. hématocrite. Trimis de gall, 13.09 …   Dicționar Român

  • hematocrit — [hem′ə tō krit΄, hē′mətō krit; hi mat′əkrit΄] n. [< HEMATO + Gr kritēs, a judge < krinein, to separate: see HARVEST] 1. a small centrifuge or its calibrated tube used to determine the relative volumes of blood cells and fluid in blood 2.… …   English World dictionary

  • Hematocrit — 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… …   Medical dictionary

  • hematocrit — noun 1. the ratio of the volume occupied by packed red blood cells to the volume of the whole blood as measured by a hematocrit • Syn: ↑haematocrit, ↑packed cell volume • Hypernyms: ↑ratio 2. a measuring instrument to determine (usually by… …   Useful english dictionary

  • hematocrit — noun Etymology: International Scientific Vocabulary hemat + Greek kritēs judge, from krinein to judge more at certain Date: circa 1903 the ratio of the volume of red blood cells to the total volume of blood as determined by separation of red… …   New Collegiate Dictionary

  • Hematocrit — zwei Blutproben, rechts frisch abgenommen, links mit sedimentierten zellulären Bestandteilen. Dieser Anteil stellt den Hämatokrit dar Hämatokrit (Abkürzung: Hct, Hkt oder Hk) bezeichnet den Anteil aller zellulären Bestandteile am Volumen des… …   Deutsch Wikipedia

  • hematocrit — noun a) The percentage (by volume) of packed red blood cells in a centrifuged sample of blood b) A centrifuge used to analyze the relative amount of red blood cells and plasma in blood …   Wiktionary

  • hematòcrit — he|ma|tò|crit Mot Pla Nom masculí …   Diccionari Català-Català

  • hematocrit — n. centrifuge for separating blood cells from plasma; relationship between the volume of cells and the volume of blood separated by a centrifuge …   English contemporary dictionary

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