METHOD FOR DETERMINING FIBRINOGEN DURING RECALCIFICATION OF CITRATE PLASMA AND EVALUATING ITS FUNCTIONALITY

摘要

FIELD: medicine.;SUBSTANCE: invention refers to medicine, namely to laboratory diagnostics and can be used for determination of fibrinogen in recalcification of citrate plasma and evaluation of its functionality. Essence of method consists in recalcification of blood plasma with calcium chloride with subsequent registration of degree of coagulation on photometer for enzyme immunoassay. In order to increase the accuracy of the test, polyethylene glycol with a molecular weight of 3350 is used as an activator of the fibrin stabilizing factor. Reaction is started in parallel 2 series by adding 0.25 M calcium chloride solution to sample containing citrate plasma, PEG-3350 and VBS buffer with pH 7.4, thoroughly mixed, absorbance of samples is measured, then incubated for 60 min at 37 °C, in the first series of the experiment, the protein content in the fibrin clot is determined by a standard method using a biuret reagent, in the second series of experiments, the plasma coagulation is determined photometrically by changing the turbidity of the samples at wavelength of 450 nm with measurement intervals of 0 and 60 min, fibrinogen content is calculated by formula: FG (g/l) = ΔA₄₅₀×5.12, where: ΔA₄₅₀ – change of optical density of sample in second series, with plasma coagulation; 5.12 is a coefficient for transfer of changes in optical density of the sample when plasma coagulation is in g/l, which is the ratio of protein in the fibrin clot to change in optical density in the sample during plasma coagulation, calculating fibrinogen functionality as a difference between fibrinogen values determined by this method and using the Claus method, calculating difference in % of protein in fibrin clot and difference of more than 10 % is defined as impaired functionality of fibrinogen.;EFFECT: using this method enables determining the amount of fibrinogen and its functionality, which enables to conduct wide screening and detect people prone to thrombosis.;1 cl, 5 tbl, 1 dwg