Syphilis is a sexually transmitted infection caused by Treponema pallidum.

The VDRL test detects non‑specific antibodies (reagin) that react with cardiolipin antigen.

Clinical uses include:

Screening for syphilis infection.

Monitoring treatment response in syphilis patients (titers decrease after successful therapy).

Supporting diagnosis in patients with neurological or atypical symptoms (VDRL can be performed on cerebrospinal fluid for neurosyphilis).

Often performed alongside treponemal tests (TPHA, FTA‑ABS, ELISA) for confirmation.

Analyte: Reagin antibodies in serum (or CSF).

Normal Result: Negative (no antibodies detected).

Abnormal Findings:

Positive VDRL: Suggests syphilis infection (active or past).

Titers: Higher titers indicate active disease; falling titers suggest treatment response.

False positives: May occur in pregnancy, autoimmune diseases, malaria, or other infections.

Clinical Use:

Provides a simple, inexpensive screening tool for syphilis.

Helps guide diagnosis, monitoring, and treatment planning.

Supports infectious disease, dermatology, neurology, and sexual health evaluations.