I. Rapid plasma reagin circle card test (RPR) can be used for syphilis screening, while its quantitative test can be used for efficacy observation. However, it should be noted that: 1. False-positive reactions (1) acute false-positive reactions: duration < 6 months, seen in viral infections (hepatitis, infectious mononucleosis, chickenpox, measles, viral pneumonia, etc.), malaria, immunization, pregnancy and experimental or technical errors. (2) Chronic false-positive reaction: duration > 6 months, more common in women, seen in connective tissue disease (e.g. SLE), diseases with immunoglobulin abnormalities, leprosy, elderly, malignancy and narcotic addiction. The titer of false positive reactions is generally low, about 1:8 or less, but in a few cases it may be very high. In addition experimental errors (temperature, titer, time, reagents, phosphate buffer or saline is contaminated), etc. 2, syphilis spirochete antigen serologic test: commonly used in clinical practice (1) fluorescent syphilis spirochete antibody absorption test (FTA-ABS): the gold standard for diagnosis. (2) Syphilis spiral particle agglutination test (Treponema Pallidum Particle Agglutination, TPPA) is a syphilis-specific test used to confirm the diagnosis of syphilis test, can be positive for life after cure, not as an indicator of efficacy observation, rarely false positive. However, there is a 1% biological false positive, such as lupus erythematosus can make FTA-ABS false positive; infectious mononucleosis heterophilic antibodies can make TPPA false positive; leprosy patients can have up to 40% false positive non-specific test, specific test can also be positive.