Syphilis laboratory findings
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Aysha Anwar, M.B.B.S[2]
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Overview
Darkfield examinations and tests to detect T. pallidum in lesion exudate or tissue are the definitive methods for diagnosing early syphilis.
Laboratory Findings
- Darkfield examinations and tests to detect T. pallidum in lesion exudate or tissue are the definitive methods for diagnosing early syphilis.
- Although no T. pallidum detection tests are commercially available, some laboratories provide locally developed PCR tests for the detection of T. pallidum.
- A presumptive diagnosis of syphilis is possible with the use of two types of serologic tests:
- Nontreponemal tests (e.g., venereal disease research laboratory (VDRL) and rapid plasma reagent test) and
- Treponemal tests (e.g., fluorescent treponemal antibody absorbed (FTA-ABS) tests, the T. pallidum passive particle agglutination (TP-PA) assay, various enzyme immunoassays, and chemiluminescence immunoassays).
- The use of only one type of serologic test is insufficient for diagnosis, because each type of test has limitations, including the possibility of false-positive test results in persons without syphilis.
- False-positive nontreponemal test results can be associated with various medical conditions unrelated to syphilis, including autoimmune conditions, older age, and injection-drug use;[1] [2] therefore, persons with a reactive nontreponemal test should receive a treponemal test to confirm the diagnosis of syphilis.
- Nontreponemal test antibody titers may correlate with disease activity and may reverse following treatment.
- Trepenomal test antibody titres once positive remains positive for the rest of life regardless of treatment or disease activity.
References
- ↑ Nandwani R, Evans DT (1995). "Are you sure it's syphilis? A review of false positive serology". International Journal of STD & AIDS. 6 (4): 241–8. PMID 7548285.
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(help) - ↑ "www.aphl.org" (PDF). Retrieved 2012-12-19.