Anti-phosphatidylserine prothrombin antibodies as a predictor of the lupus anticoagulant in an all-comer population.

A cohort of 166 eligible patients was identified. Seventy-one percent were female, 89% White, 15% with SLE, and 21% with APS. The aPSPT was found to be the most specific to the LAC. Specificity of IgG aPSPT was 100% (96%-100%) and IgM aPSPT was 97% (91%-100%) to the LAC. Corresponding positive predictive value for IgG aPSPT was 100% (89%-100%) and IgM aPSPT was 95% (84%-99%). In contrast, the sensitivities of aPSPT to the LAC were less robust, only in the 40%-50% range. The findings validate previously reported findings and lends extension to an all-comer population. These findings corroborate aPSPT as a potentially useful clinical marker of the LAC.