PAI-1 is a primary regulator of fibronlysis. It is found in many tissues and cell types including macrophages / monocytes, hepatocytes, vascular endothelia, adipose tissue of the heart and lungs and in platelets. The amount of PAI-1 in plasma is related to various thrombotic and fibrinolytic complications.
A lack of PAI-1 activity is linked to bleeding disorders wherein routine hemostatic screening tests are normal. High levels of PAI-1 activity are present in patients who suffers from myocardial infarction, haemolytic uremic syndrome and stroke.
The assay is a two-stage colorimetric test.
» In the first part, samples are incubated with a known amount of tPA, this allows PAI-1 to react with tPA
» In the second part, residual tPA activity converts plasminogen to plasmin. This in turn hydrolyzes a plasmin chromogenic substrate, SPECTROZYME® PL.
PAI-1 in the plasma is determined as the difference between the amount of tPA added and the amount of tPA recovered.