What laboratory tests are essential for the diagnosis of Antiphospholipid Syndrome (APS) in a patient with a history of thrombosis?

For a patient with a history of thrombosis, the essential laboratory tests for the diagnosis of Antiphospholipid Syndrome (APS) involve the detection of specific antiphospholipid antibodies (aPL) ³. These include:

• Lupus anticoagulant (LA) (Zahidin et al., 2024; Devreese et al., 2025)
• Anti-cardiolipin antibodies (aCL) (Zahidin et al., 2024; Devreese et al., 2025)
• Anti-beta2-glycoprotein I (aβ2GPI) antibodies (Zahidin et al., 2024; Devreese et al., 2025)

To establish a definitive diagnosis of APS, these antibodies must be detected on at least two separate occasions, with a minimum of 12 weeks between the tests (Vandevelde and Devreese, 2022; Devreese et al., 2025). Guidance on the laboratory detection and interpretation of these antiphospholipid antibodies for APS diagnosis is provided by expert subcommittees, such as the ISTH-SSC Subcommittee on Lupus Anticoagulant/Antiphospholipid Antibodies (Devreese et al., 2025).