Use

The assay detects IgM-class antibodies targeting the phosphatidylserine–prothrombin complex in serum or plasma. As non‑criteria antiphospholipid antibodies, PS/PT IgM positivity may support diagnosis of antiphospholipid syndrome (APS) and correlate with lupus anticoagulant presence, particularly in patients on anticoagulant therapy where lupus anticoagulant testing may be unreliable. A positive result may stratify thrombosis risk in autoimmune conditions such as APS or systemic lupus erythematosus. Results in IgM units; cutoff ≤ 30 units. Difference in assay methods may limit inter‑laboratory comparability.