ACA is an autoimmune antibody and the role of autoimmune factors in the pathogenesis of patients with habitual abortion is well established. It is known that ACA may cause miscarriage through the following pathways: (1) ACA acts on phospholipid-dependent antigens on the surface of the trophectoderm, affecting its adhesion, fusion and differentiation processes, causing insufficient formation of syncytial trophectoderm cells, resulting in reduced uterine receptivity to the embryo and decreased secretion of placental hormones such as hCG and hPL that maintain pregnancy; (2) disturbing the balance of thromboxane A2 and prostacyclin, leading to platelet aggregation and formation of microthrombi, causing placental infarction and poor pregnancy outcome; (3) ACA acts on the placenta and causes placental infarction. (3) ACA acts on the phospholipids of placental vascular endothelial cell membranes, causing placental thrombosis and vasoconstriction, reduced placental blood flow, or placental vasculitis, resulting in fetal death due to insufficient oxygen supply and nutrition; (4) ACA interferes with the effect of calcium-dependent phospholipid-binding protein-V, which is an anticoagulant property of ACA-positive patients with recurrent miscarriages were found to have significantly reduced calcium-dependent phospholipid-binding protein-V. Its main pathological changes are endothelial damage, platelet aggregation, hypercoagulable state and finally lead to intravascular thrombosis. Fu Jinhua, Department of Obstetrics, Weifang People’s Hospital The immunopathological reaction between ACA and phospholipids acts through β2-GPI. recent studies have found that some APS patients are negative for ACA and positive for anti-β2-GPI antibodies. anti-β2-GPI antibodies are also able to exert pathological effects similar to those of ACA by binding to β2-GPI. b2-GPI, also known as apolipoprotein H, is synthesized by hepatocytes. Synthesized by hepatocytes, b2-GPI is a single-chain glycoprotein abundant in plasma with a relative molecular mass of 50,000. It binds to lipoproteins in plasma and has a large number of positively charged amino acid sequences in its functional regions 1, 2 and 5. Upon binding to substances with anionic phospholipids, b2-GPI reveals its hidden antigenic epitopes, leading to the production of anti-b2-GPI antibodies. In vitro tests have revealed that b2-GPI may have a natural anticoagulant effect, and that binding of anti-b2-GPI antibodies to anionic phospholipids can lead to vascular damage through a variety of mechanisms, creating a procoagulant state in vascular endothelial cells, increasing platelet adhesion and aggregation to endothelial cells, and disturbing the balance between coagulation and anticoagulation factors, which can eventually lead to thrombosis. It is generally considered to have a stronger correlation with thrombosis than ACA [12]. Therefore, combined detection of anti-β2-GPI antibody and ACA may increase the accuracy of APA detection in RSA. The results of this study showed that only 18.7% (78/417) were positive for ACA, 7.7% (32/417) were positive for anti-β2-GPI antibodies, 4.6% (19/417) were double positive for ACA and anti-β2-GPI antibodies, and the total positive rate of ACA and/or anti-β2-GPI antibodies was 21.8% (91/417). Therefore, routine combined testing of ACA and anti-β2-GPI antibodies is necessary to improve the detection rate and accuracy of APA in patients with recurrent miscarriage. We found that the positive rate of 3 consecutive tests was only 12.47%, and the positive rate increased gradually with the increase of the number of tests, and the positive rate of 12 tests was up to 21.82%. The positive rate of the 13th and 14th tests was the same as that of the 12th test (21.82%), and after 12 consecutive tests, increasing the number of tests could not improve the positive detection rate. Among the 91 APA-positive patients diagnosed, the detection rate was 68.13% for 4 times; 81.32% for 5 times (c2=4.189, p=0.041); 90.11% for 7 times; and more than 93.41% for >7 times, showing that the detection rate decreased gradually with the increase in the number of tests. Therefore, in order to reduce the leakage rate and misdiagnosis rate of APA testing, it is recommended that screening for the etiology of recurrent miscarriage autoantibodies should be performed once every 3 weeks and at least 5 times consecutively under the condition of excluding interfering factors such as acute infection, which will help to improve the accuracy of APA detection.