Fluorescent Treponemal Antibody (FTA - Abs)

A positive FTA-ABS (fluorescent treponemal antibody absorption) means antibodies to Treponema pallidum have been detected, indicating current or past syphilis infection. It’s a treponemal confirmatory test that often remains positive for life and cannot reliably distinguish active versus treated disease. Further evaluation (clinical exam, non-treponemal tests like RPR/VDRL) and appropriate management, including partner testing, are recommended.

A positive fluorescent antibody test indicates that specific antibodies or antigens targeted by the assay were detected in the sample, suggesting a current or past infection or an immune response. Interpretation depends on test type, timing (acute vs convalescent), and clinical context; follow-up testing or correlation with symptoms may be needed to confirm infection or immunity because false positives and cross‑reactivity can occur.

A positive treponemal antibody means the person has mounted an immune response to Treponema pallidum, indicating past or current syphilis infection. These antibodies often remain detectable for life, so a positive test alone can’t distinguish active, treated, or latent disease. Clinicians use non-treponemal tests (e.g., RPR/VDRL), clinical history, and repeat testing to determine activity and need for treatment.

In India, FTA‑ABS testing typically costs around ₹1,000–3,000 at private diagnostic centres; prices vary by city, lab and whether additional reporting/consultation is included. Many government hospitals, public health clinics or HIV/TB programme centres may provide confirmatory syphilis testing free or at subsidised rates. Always check nearby accredited labs for exact pricing.

If a syphilis test is positive, confirm with treponemal and non‑treponemal tests, get clinical staging and HIV testing, and start recommended antibiotic treatment—typically intramuscular benzathine penicillin. Notify and test recent sexual partners, avoid sexual activity until cleared, and attend follow‑up serology to confirm response. Pregnant people need urgent treatment to prevent fetal infection.

TPHA and FTA-ABS are not the same test but serve the same purpose: both are treponemal serologic assays that detect antibodies to Treponema pallidum. TPHA is an agglutination test using coated red cells; FTA-ABS uses fluorescent-labeled antibodies. Both help confirm syphilis and usually remain positive after treatment; neither reliably distinguishes active from past infection.