PPA-2A
Set of reagents for determining the activity of antithrombin III by chromogenic method (Rechrom-ATIII) according to TU 21.20.23-062-05595541-2017. Designed for quantitative determination of antithrombin III activity in blood plasma using a chromogenic method.
Antithrombin III (ATIII) or heparin cofactor is the main antagonist of thrombin in the formation of this enzyme in the blood. Inherited and acquired deficiency of ATIII in the blood leads to the development of disseminated intravascular coagulation and, in some cases, acute thrombosis. Reduced concentration of ATIII is observed in patients with liver diseases (cirrhosis), with nephrotic syndrome due to excretion of the inhibitor in the urine. Injections of heparin and oral contraceptives reduce the concentration of ATIII.
Method principle: The method for determining the activity of ATIII is based on the ability of ATIII to neutralize thrombin in the presence of heparin. ATIII activity is determined in plasma by adding an excess of thrombin to it. In this case, thrombin is inhibited by the ATIII-heparin complex in proportion to the amount of ATIII in the plasma. The remaining amount of thrombin catalyzes the cleavage of para-nitroaniline (pNA) from a synthetic chromogenic substrate. The absorption of free pNA, determined at 405 nm, is inversely proportional to the activity of ATIII.
The process proceeds according to the following scheme: ATIII + heparin (excess) ⇒ ATIII-heparin. ATIII-heparin + thrombin (excess) ⇒ ATIII-heparin-thrombin + thrombin (remainder). Substrate-pNA + thrombin (remainder) ⇒ Peptide + pNA.
To construct a calibration curve, a plasma calibrator with a known ATIII activity (A) is used. On the ordinate axis (Y), the optical density values obtained for each dilution of the plasma calibrator are plotted on a linear scale, and on the abscissa axis (X), the antithrombin III activity in % is plotted on a linear scale.
Using the calibration curve and the clotting time value of the test sample, the ATIII activity is determined in %.
Composition:
Human Thrombin with Heparin 4х40 IU
Calibration Plasma 1х1 ml
Chromogenic substrate 4х8 mkm
Imidazole Buffer 1х5 ml
Kit for 120 tests on coagulometer Sysmex and 320 tests on coagulometer ACL.
