Use

PAI‑1 (Plasminogen Activator Inhibitor‑1) antigen levels are measured to assess fibrinolytic balance; elevated levels are associated with increased risk of arterial thrombosis, such as premature myocardial infarction, and can act as an acute‑phase reactant increasing post‑event. Additionally, studies suggest PAI‑1 may serve as a prognostic marker in early‑stage breast cancer.