Assessment of the prevalence of anti-phosphatidylserine-prothrombin antibodies (aPS/PT) with OAPS and SN-OAPS in Chinese patients.This retrospective study proceeded at Ren Ji Hospital, Shanghai, China, from January 2019 to January 2020. Two hundred eleven OAPS, 68 SN-OAPS, 81 disease controls, and 30 healthy donors were enrolled. IgM and IgG aPS/PT, IgM/IgG - aCL, and IgM/ IgG/ anti-β2GPI antibodies were tested by ELISA while LAC was tested by clotting assays. All the patients were followed up and tested at least twice over 12 weeks apart.Thirty-three OAPS (15.64%) and 31 SN-OAPS (45.59%) were positive for aPS/PT. aPS/PT IgM showed a high Youden index (.813), which classified OAPS and SN-OAPS patients from healthy controls and other autoimmune diseases. aPS/PT showed a stronger relationship with LAC. Of the 25 OAPS women positive for IgM aPS/PT, 19 (79%) LAC were positive, while of the eight women positive for IgG aPS/PT, 100% were found LAC positive.aPS/PT antibody showed an efficient diagnostic value for Chinese patients with OAPS and SN-OAPS, which could be a potential risk predictor for obstetric complications.