CPT® Code 85420

The CPT® Code 85420 refers to a laboratory test that assesses fibrinolytic factors and inhibitors, specifically measuring plasminogen activity, excluding antigenic assays. Plasminogen is a crucial protein produced by the liver, existing in an inactive form within the bloodstream until it binds to a clot or cell surface. Upon activation, plasminogen converts to plasmin through the action of various activators, including tissue plasminogen activator (tPA), urokinase plasminogen activator (uPA), kallikrein, and factor XII (Hageman). This test is significant as it helps in identifying abnormalities in plasminogen levels, which can be indicative of various medical conditions. Decreased plasminogen levels may arise from inherited genetic disorders or can be acquired due to conditions such as disseminated intravascular coagulation (DIC), liver disease, thrombolytic therapy, or the use of L-asparaginase. Conversely, elevated plasminogen levels have been associated with factors such as anabolic steroid use, hypothyroidism, hormonal contraceptives, infections, inflammation, trauma, and pregnancy. The measurement of plasminogen activity is particularly useful in evaluating patients who experience incidental or recurrent thromboembolic events, have a family history of arterial or venous thrombophilia, or present with ligneous conjunctiva. In cases where plasminogen activity is found to be abnormal, further testing for plasminogen antigen (CPT® Code 85421) may be warranted to investigate potential genetic disorders. The test is performed on a blood sample, which is obtained through a separately reportable venipuncture, and the analysis is conducted on platelet-poor plasma using a chromogenic assay.