The antiphospholipid syndrome (APS) or Hughes syndrome is a systemic autoimmune disorder characterized by a combination of arterial and/or venous thrombosis, and recurrent fetal loss, and elevated levels of antiphospholipid antibodies (aPL). The aim of this study was to investigate the importance of aPL type and level for non-criteria-related events, thrombotic and neurological and cardiac non-thrombotic manifestations in APS patients. Our study included 374 patients: 260 with primary APS (PAPS) and 114 with APS associated with systemic lupus erythematosus (SLE) (SAPS). Our study showed that certain aPL type with certain level correlated with non-criteria as well as thrombotic and neurological and cardiac non-thrombotic manifestations, suggesting their predictive role. We also concluded that any aPL type and level is a risk factor for thrombosis and that there is strong link between some non-thrombotic neurological and cardiac manifestations in APS patients suggesting complexity and...