According to the classification criteria of antiphospholipid syndrome (APS), lupus anticoagulant (LA), anticardiolipin (aCL) and anti-β2-glycoprotein I antibody (aβ2GPI)assays are independent risk factors for the occurrence of vascular thrombosis and pregnancy loss.1 It is generally accepted that patients carrying multiple positivity for antiphospholipid (aPL) antibodies have a more severe disease and higher recurrence rate despite treatment. On the other hand, the stable positivity of a single test is sufficient to classify a patient as having APS.2 As a consequence, clinicians have been wondering whether patients with similar clinical features, but with different positivity patterns (profiles) in the three aPL tests, should be considered completely comparable or not.

We retrospectively studied 3088 consecutive patients who were referred within a 24-month period (January 2007 to January 2009) to coagulation laboratory for the following indications: (A) suspected thrombophilia (thrombotic diathesis), (B) suspected obstetric APS, …