Venereal Disease Research Laboratory (VDRL)

Syphilis is a sexually transmitted infection caused by the spirochete, or spiral-shaped, gram-negative bacteria Treponema pallidum. The clinical manifestations of syphilis depend upon the stage of disease. The signs and symptoms of primary syphilis infection include a painless, firm, and round ulcer called a chancre. Secondary infection presents with a diffuse, symmetric macular (i.e., flat) or papular (i.e., raised) rash involving the entire trunk and extremities, including the palms and soles.  

Tertiary syphilis which can be classified as early latent syphilis (<1 year) or late latent syphilis (>1 year or unknown), presents with aortitis (i.e., inflammation of the aorta) or aortic aneurysm (i.e., widening of the aorta), and disseminated gummas (i.e., tumor-like growth of tissue).   

Other less specific symptoms of syphilis include aortic insufficiency, cranial nerve dysfunction, chronic headache, meningitis, and other signs of meningovascular disease, including cerebrovascular accidents.  

Screening for syphilis requires serologic testing, including the venereal disease research laboratory (VDRL) test. Treatment of disease involves intravenous antibiotics, such as penicillin G, followed by prolonged monitoring to ensure successful eradication of the infection.  

The venereal disease research laboratory (VDRL) test is a nontreponemal screening test for syphilis. Nontreponemal indirectly measures the body’s response to cellular damage caused by the syphilis spirochete. In addition to VDRL, other nontreponemal tests such as the rapid plasma reagin (RPR) can be used for screening, however, the VDRL remains the most common syphilis screening test worldwide.  

The VDRL can be performed via venipuncture or through a lumbar puncture to obtain cerebrospinal fluid (CSF). The latter is typically reserved for cases where neurosyphilis is suspected. In a healthy person, the test is negative, however false positive results (i.e., the test states someone has syphilis, when in fact they do not) can occur in up to 11% of cases. Thus, obtaining a proper medical history and performing a thorough review of symptoms and physical examination are important when making a diagnosis of syphilis.   

In addition to the VDRL, there are other methods used to screen for syphilis, including direct observation of the spirochete by dark field microscopy and treponemal serologic antibody studies. In contrast to nontreponemal tests, treponemal tests directly detect antibodies to Treponema pallidum proteins. Examples include fluorescent treponemal antibody absorption (FTA-ABS) test and Treponema pallidum hemagglutination assay. These specific treponemal tests help to diagnose syphilis after cost-effective screening tests are performed.   

Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum. It typically presents in three stages: primary, secondary, and tertiary. Screening for syphilis is performed using nontreponemal tests such as the VDRL, whereas confirmation relies on treponemal testing such as the FTA-ABS test.  

The VDRL mnemonic describes conditions known to cause false positives on the venereal disease research laboratory (VDRL) blood test for syphilis: viral infections (e.g., mononucleosis, hepatitis), drugs (e.g., procainamide, chlorpromazine), rheumatic fever, and lupus and leprosy.