Hematocrit ( hematocrit value , hematocrit number ) - the volume of red blood cells in the blood. Sometimes hematocrit is defined as the ratio of the total volume of all shaped elements ( red blood cells , white blood cells , platelets ) to the total blood volume [1] ; the difference, however, is small, since 99% of the total volume of the formed elements falls on red blood cells. Hematocrit (Ht) is expressed as a percentage of the total blood volume (then it is indicated in%), or in liters per liter (l / l) - then it is indicated by decimal fraction (accurate to hundredths), corresponding to the proportion of shaped elements in 1 liter of blood (450 ml of cells in 1 liter of blood = 0.45 L / L = 45%).
36β48% of human blood consists of uniform elements, 52β64% of plasma is liquid intercellular substance containing 90β93% of water and 7β10% of dry matter ( proteins , carbohydrates , salts ) [2] . Hematocrit is the ratio of the volumes of uniform elements and blood plasma. Normally, the hematocrit of men is 0.40-0.48, and women - 0.36-0.46. In newborns, the hematocrit is approximately 20% higher, and in young children, approximately 10% lower than in an adult.
The hematocrit is determined using a special graduated glass tube - hematocrit , which is filled with blood and centrifuged , after which it is noted which part of the tube is formed by blood cells. The use of automatic analyzers is also becoming increasingly widespread.
Content
Diseases and conditions accompanied by a change in hematocrit
Hematocrit Increased
- Erythrocytosis (an increase in the number of red blood cells):
- primary ( erythremia )
- caused by hypoxia of various origin (for example, adaptation to high altitude conditions)
- neoplasms of the kidneys, accompanied by increased formation of erythropoietin
- polycystic kidney disease and hydronephrosis
- Reducing the volume of circulating plasma ( burn disease , peritonitis , etc.)
- Dehydration
- Leukemia
Hematocrit reduced
- Anemia
- Increase in circulating blood volume:
- pregnancy (especially the second half - physiological hemodilution of pregnant women);
- infant age (characterized by moderate decline)
- hyperproteinemia
- Overhydration
Hematocrit in mammals
In different species of mammals, the ratio of the volumes of the formed elements of blood and plasma varies. So, the average hematocrit value is noticeably higher in some species ( humans - 42, dog - 45, cat - 40, rat - 43, mouse - 40, koala - 43, echidna - 48%) and lower in others ( cow - 30, sheep and pig - 33%) [3] [4] . Significantly increased hematocrit values ββare characteristic of marine mammals : in a sea ββotter, hematocrit is 52.5, northern elephant seal - 57, bowhead whale - 59 and Weddell seal - 63.5% [5] [6] .
See also
- Hematology
- Anemia
Notes
- β Large Russian-English medical dictionary / Antonyan R.G., Benyumovich M.S., Bolotina A. Yu. Et al. - M .: Russo, 2000. - 704 p. - ISBN 5-88721-142-3 . .
- β Histology, cytology and embryology. 6th ed. / Ed. Yu. I. Afanasyev, S. L. Kuznetsova, H. A. Yurina. - M .: Medicine, 2004 .-- 768 p. - ISBN 5-225-04858-7 . . - S. 166.
- β Windberger U., Bartholovitsch A., Plasenzotti R., Korak K. J., Heinze G. Whole blood viscosity, plasma viscosity and erythrocyte aggregation in nine mammalian species: reference values ββand comparison of data // Experimental Physiology , 2003, 88 (3) . - P. 431-440.
- β Baskurt O. K., Marshall-Gradisnik S., Pyne M., Simmonds M., Brenu E., Christy R., Meiselmane H. J. Assessment of the hemorheological profile of koala and echidna // Zoology (Jena) , 2010, 113 (2) . - P. 110-1117. - DOI : 10.1016 / j.zool.2009.07.07.003 .
- β Wickham L. L., Costa D. P., Elsner R. Blood rheology of captive and free-ranging northern elephant seals and sea otters // Canadian Journal of Zoology , 1990, 68 (2). - P. 375-380. - DOI : 10.1139 / z90-053 .
- β Castellini M. A., Baskurt O., Castellini J. M., Meiselman H. J. Blood rheology in marine mammals // Frontiers in Physiology , 2010, 1 . - P. 146-1-146-8. - DOI : 10.3389 / fphys.2010.00146 .