Non-criteria antiphospholipid syndrome: A nomenclature proposal

The classification criteria for antiphospholipid syndrome (APS) generate discussion, with a growing impression that certain patients not fulfilling these criteria might be inadequately excluded from the classification. Nonetheless, these non-criteria patients are heterogeneously defined across different publications. We reviewed the non-criteria APS subgroups depicted in the literature and attempted to organize these subsets in a nomenclature proposal that could be used for research purposes. We established four potential patient profiles, grouped under the broad term non-criteria APS: (A) Seronegative APS: patients fulfilling clinical criteria, plus non-criteria manifestations, with persistently negative antiphospholipid antibodies (aPL); (B) Clinical non-criteria APS: patients with non-criteria manifestations, plus aPL positivity fulfilling the classification criteria; (C) Incomplete laboratory APS: patients fulfilling clinical criteria, plus positive aPL, but not fulfilling the classification criteria (low titer aPL); and (D) Laboratory non criteria APS: patients fulfilling clinical criteria, with negative or low titer criteria aPL, plus positive non criteria aPL. This categorization could allow for a more homogeneous research approach to APS, enabling more sustained and universal conclusions.