Comparison of two immunochemical assays for measuring thrombin-activatable fibrinolysis inhibitor concentration with a functional assay in patients with acute coronary syndrome☆

Abstract 

TAFI was measured as relative activity concentration (Pefakit) and antigen concentration (Haemochrom and Asserachrom) both acutely and during convalescence in patients suffering from acute coronary syndrome, and in a group of healthy controls. There was a rather weak but significant correlation between the activity and antigen concentrations. The results obtained by the Haemochrom method, assumed to measure the concentrations of all forms of TAFI, were lower than those by the Asserachrom method although the latter is assumed to only measure the pro-TAFI concentration. Both immunoassays gave lower results than the functional method (Pefakit). The patients in the convalescence phase showed a higher activity concentration than the healthy controls. The Asserachrom showed a higher concentration in the acute and convalescence phases of the patients compared to the controls, whereas the Haemochrom did not show any such difference. This could be related to different species of the TAFI molecule and thus different reactivity to the antibodies. Therefore the optimal choice of assay for determination of TAFI in different clinical studies is of importance. The Pefakit and Asserachrom seem to be appropriate candidates.

Keywords: ELISA, Polymorphism, Kinetic assay, Acute coronary syndrome (ACS), TAFI, Chromogenic substrates