Alpha-2-antiplasmin is the major circulating inhibitor of plasmin. It plays a role in the regulation of intravascular fibrinolysis. Decreased levels of alpha-2-antiplasmin may play an important role in the increased capacity of the fibrinolytic function and may be beneficial in the treatment of thrombotic diseases, acute pulmonary embolism, and hepatic repair. The sensitive quantitative measurement of total human alpha-2-antiplasmin antigen in samples is easily performed with this 96 well strip format ELISA kit. The normal human concentration of antiplasmin is 70 ug/ml in plasma and 47.6 ug/ml in serum. The assay measures total antiplasmin in the 0.1-100 ng/ml range. Samples giving human antiplasmin levels above 100 ng/ml should be diluted in blocking buffer before use. A 1:10,000-20,000 dilution for plasma is suggested for best results. Human antiplasmin will bind to the capture antibody coated onto a micro titer plate. Free and complexed antiplasmin will bind to the plate and will be detected by the assay. This kit does not cross react with mouse antiplasmin. After appropriate washing steps, biotin labeled anti human antiplasmin primary antibody binds to the antiplasmin. Excess antibody is washed away, and bound antibody is reacted with peroxidase conjugated streptavidin. TMB substrate is used for color development at 450 nm. Color development is proportional to the concentration of antiplasmin in the samples. A standard calibration curve is prepared using dilutions of purified antiplasmin and is measured along with the test samples. All reagents and standards are provided in these ELISA kits.