Development of a latex immunoturbidimetric assay for the automated measurement of alpha(2) plasmin inhibitor-plasmin complex in human plasma

We have developed a rapid, sensitive, and quantitative latex immunoturbidim etric assay for the measurement of alpha(2) plasmin inhibitor-plasmin inhib itor complex (PIC) in human plasma. The method is based on the latex agglut ination reaction using a suitable pair of monoclonal antibodies. One reacts with plasmin and the other reacts with or, plasmin inhibitor. In this assa y, we added 6-aminohexanoic acid to the reaction buffer in order to avoid t he nonspecific latex agglutination caused by precursor proteins such as pla sminogen, We used this method with an automatic analyzer HITACHI 7150 (Hita chi Ltd., Hitachi, Japan) and measured PIC within the range of 0.2 to about 50 mg/mL in only 15 minutes. The precision indices (CV%) of intra-assays a nd interassays were <4.4% and <3.4%, respectively. The influence of plasmin ogen or or, plasmin inhibitor on plasma was negligible, Based on these resu lts, it is considered that this method would be useful for evaluation of a broad spectrum of fibrinolytic disorders, particularly disseminated intrava scular coagulation.