Can serum antibody testing detect syphilis? What are the staging and main clinical manifestations of syphilis

Syphilis serum test is a diagnostic test used for syphilis diseases. According to the antigens used, syphilis serum testing can be divided into non syphilis spirochete antigen serum testing and syphilis spirochete antigen serum testing. In clinical practice, both results are positive and can be diagnosed as syphilis infection, i.e. current syphilis, and treatment for syphilis needs to be initiated.

How about syphilis serum testing

According to the antigens used, syphilis serum tests are divided into

(1) The non syphilis spirochete antigen serum test uses Cardiolipin as the antigen to determine the anticardiolipin antibody in the serum, also known as the reagin. This test has high sensitivity, low specificity, and is prone to biological false positives. After sufficient treatment in early syphilis patients, the reactive hormone can disappear. In early untreated patients, the reactive hormone can also be reduced or disappeared in some patients. Currently, it is generally used as a screening and quantitative test to observe efficacy, recurrence, and reinfection.

1. The VDRL (Venereal Disease Research Laboratory Trial) should pay attention to phospholipids, lecithin, and cholesterol as antigens, which can be used for quantitative and qualitative testing. The reagents and serum are standardized, and the cost is low. This method is commonly used and easy to operate, requiring a microscope to read the results. The disadvantage is that the sensitivity of syphilis is not high.

2. Rapid plasma reagin test (RPR): VDRL antigen modification, with sensitivity and specificity similar to VDRL, with the advantage of readable results to the naked eye.

3. The unheated serum reagin glass test (USR) is also an improvement of VDRL antigen, with sensitivity and specificity similar to VDRL.

(2) Treponema pallidum antigen serum test: Use live or dead Treponema pallidum and its components as antigens to measure anti Treponema pallidum antibodies. The sensitivity and specificity of this test are high, and it is generally used for confirmatory testing. This test detects anti Treponema pallidum IgG antibodies in the serum, which can persist for a long time even after sufficient treatment. The serum reaction is still positive, so it cannot be used to observe the therapeutic effect.

What are the staging manifestations of syphilis

1、 Stage 1 syphilis: The skin lesion in this stage is hard chancre, which is a single round or elliptical nodule of about 1cm in size, with a clear boundary and a deep base resembling rubber or cartilage, without conscious pain or tenderness; The surface is flat, with obvious infiltration, and there is an ulcer in the center, which turns pale red in the early stage and gray in the later stage; The secretion from the hard chancre ulcer surface is mostly serous and contains a large amount of spirochetes, which is highly infectious; Individual patients may experience more than 2 hard chancre, but it is rare.