Volume 11,Issue 5
Reasons for False Positives in Syphilis Serological Tests and Key Points of Identification
Objective: To analyze the causes and identification points of false positives in syphilis serological tests. Methods: From August 2024 to July 2025, 1050 patients who underwent syphilis serological testing were selected for data analysis in the Laboratory Department of the Institute of Dermatology Prevention and Treatment. Toluidine red unheated test (TRUST) and Treponema pallidum particle agglutination test (TPPA) were performed. The gold standard for diagnosis was TPPA. Single-factor χ2 test and multi-factor Logistic regression analysis were used to screen independent risk factors for false positives. Results: 14 cases (1.33%) were positive for TPPA, and the false positive rate of TRUST was 1.05%. The single-factor χ2 test results showed that the reasons for a higher false positive rate of syphilis serology include age ≥ 60 years old, combined autoimmune diseases, malignant tumors, chronic liver disease, specimen hemolysis, specimen contamination, abnormal incubation time, and use of expired reagents, p < 0.05. The results of multivariate logistic regression analysis showed that the independent risk factors for false-positive syphilis serology tests were age ≥ 60 years, combined with autoimmune diseases, malignant tumors, hemolysis of specimens, and abnormal incubation time, p < 0.05. Conclusion: Multiple factors work together to cause false positives in syphilis serology. Clinical attention should be paid to the elderly, patients with autoimmune diseases and tumors, and standard quality control and standardized operations should be carried out. Preliminary screening combined with TPPA confirmation mode and comprehensive identification combined with medical history can effectively reduce the misdiagnosis rate.
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