A Case of False Positive Syphilis Specific Antibody Detected by TPPA in Outpatients

Treponema Pallidum Particle Agglutination assay (TPPA), a commonly used laboratory serological testing method, is widely applied in clinical practice and can detect the specific antibody response in patients' bodies so as to confirm or rule out syphilis infection.

We report a case of a false-positive result for syphilis-specific antibodies in a dermatology outpatient. We used the TPPA method and chemiluminescence immunoassay (CLIA) to detect syphilis-specific antibodies, and also, the Toluidine Red Unheated Serum Test (TRUST) to detect syphilis-non-specific antibodies. For a definite diagnosis, we sent the patient's samples to Zhejiang Provincial Skin Disease Prevention and Treatment Insti-tute, where the staff used the western blot method to detect syphilis-specific IgG and IgM antibodies.

The patient's TPPA result was positive, while those of the CLIA, TRUST, western blot results were nega-tive.

The TPPA test for syphilis-specific antibodies is of great value in clinical application, though false-positive results may occur. For patients with abnormal results, various factors should be comprehensively considered, and further examinations and verifications should be carried out to ensure diagnostic accuracy.