Syphilis immunoassay


 * Tests based on monoclonal antibodies and immunofluorescence, including treponema pallidum hemagglutination assay (TPHA) and fluorescent treponemal antibody absorption (FTA-ABS) are more specific and more expensive.


 * Following positive non-treponemal tests, FTA-ABS is commonly used to confirm the diagnosis. Sensitivity ranges from 84% for detection of primary infection to approximately 100% for the diagnosis of other stages with a specificity of 96%.


 * Unfortunately, false positives can still occur in related treponomal infections such as yaws and pinta.


 * Tests based on enzyme-linked immunoassays for immunoglobulin G (IgG) and immunoglobulin M (IgM) are also used to confirm the results of simpler screening tests for syphilis.

Resources

 * Sexually transmitted diseases treatment guidelines, 2010


 * Association of Public Health Laboratories (APHL). Laboratory Diagnostic Testing for Treponema pallidum. Expert Consultation Meeting Summary Report, January 13--15, 2009, Atlanta, GA


 * CDC: Guidelines for the laboratory diagnosis of gonorrhea, chlamydia and syphilis