From Big Medical Encyclopedia

GEMATOKRITNY NUMBER (grech, haima, haimat[os] blood + krino to divide, distribute) — a volume ratio of uniform elements of blood and plasma. Of h gives an idea of the total amount of erythrocytes, characterizes degree of haemo-concentration and hemodilutions (see) at various diseases is also one of exponents of expressiveness patol, process. It serves as auxiliary size during the definition of a number of indicators of blood — volume and thickness of a separate erythrocyte, lump of the circulating blood, etc.; it is used also during the calculations in biochemical, blood analyses.

Of h is defined by a hematocrit, the conductometer (see. Conductometry ), and also nomograms.

Fig. 1. Scheme of a gematokritny nozzle: 1 — the graduated capillaries in a special nozzle; 2 — the shunt connecting a nozzle to shaft of the centrifuge. Fig. 2. Phillips's nomogram — Van-Slayka — the graphic representation of interdependence of gematokritny number (Ht) from a hemoglobin content (Hb).

Principle of definition of G. of h hematocrit consists in stratification of blood on dense and liquid speak rapidly by centrifuging. The hematocrit is two short glass graduated on 100 divisions of a capillary with dia, a gleam apprx. 1 mm in a special nozzle, edges fastens on vertical to a shaft of the engine of the centrifuge (fig. 1).

Capillaries process previously anticoagulant: rinse several times solution of heparin (1000 units in 1 ml) or 10% EDTA solution and dry up. In the prepared capillaries (definition is conducted at the same time in two capillaries) nasasyvat venous or capillary blood, several times blowing blood from a capillary on clock glass and filling it for careful hashing it with anticoagulant again. The capillaries filled with blood place in a special nozzle. Centrifuge in reference conditions: or in ordinary centrifuges with a speed of 3000 rpm within 30 min., or in special centrifuges at 16 500 rpm within 1 min. Uniform elements of blood, as having bigger ud. weight, under the influence of centrifugal force settle at the distal end of a capillary.

Volumes of uniform elements of blood and plasma count on the scale put on capillaries of a hematocrit.

Accuracy of a centrifugal method makes +3%. The main source of mistakes is connected with insufficient consolidation of a deposit of uniform elements of blood with low speeds of centrifuging.

Results of a research can be expressed in fraction: numerator — the volume of uniform elements on a scale of a capillary, a denominator — the volume of plasma (e.g., 40/60), but express to G.'s thicket of h in integers, as a percentage (e.g., 40%) — the volume of uniform elements.

Research G. of h by means of the conductometer it is offered as the express method based on measurement of conductivity of blood; the last is defined by the electric resistance of erythrocytes and finally depends on their volume.

For G.'s calculation are also offered h nomograms — graphics of functional interdependence of volume of uniform elements of blood from concentration of hemoglobin, ud. weight of blood and plasma, etc.

Phillips's nomogram — Van-Slayka (R. A. Phillips, D. D. van Slyke) represents a double scale, on to-ruyu the corresponding values G. of h and size of concentration of hemoglobin in gram-percent (fig. 2) are caused. On the known concentration of hemoglobin on the nomogram find value G. of h.

Normal amounts of G. of h at men fluctuate within 40/60 — 48/52, or 40 — 48%, at women 36/64 — 42/58, or 36 — 42%. The total amount of erythrocytes increases at burns, inborn heart diseases, a polycythemia, at long stay in mountains; decreases — at anemias, an overhydratation.

See also Blood , methods of a research.

Bibliography: The reference book on clinical laboratory methods of a research, under the editorship of E. A. Kost, page 83, M., 1975; That to - a ditch Y. Clinical laboratory trials in pediatrics, the lane with bolg., Sofia, 1968; In u of with k H. Page &of Fehler und Fortschritt der Hmatokritmethode, Dtsch, med. Wschr., S. 1362, 1970; K e r n e n J. A., Wurzel H. OkadaR. New electronic method for measuring hematocrit, J. Lab. clin. Med., v. 57, p. 635, 1961; Van Allen C.M. Hematocrit method, ibid., v. 10, p. 1027, 1925.

B. I. Krivoruchko.