Syphilis Screening Test
Syphilis screening typically uses a two-step approach: a non-treponemal test (RPR or VDRL) that detects antibodies to cellular damage from the infection, followed by a treponemal test (FTA-ABS or TP-PA) that detects antibodies to the actual syphilis bacterium. The RPR titer also tracks disease activity and treatment response.
What is Syphilis Screening (RPR/VDRL)?
RPR (Rapid Plasma Reagin) and VDRL are non-treponemal tests measuring anticardiolipin antibodies. Quantitative (reported as titer). Treponemal tests (FTA-ABS, TP-PA) are confirmatory. Reverse algorithm: some labs screen with treponemal test first. RPR titer tracks disease activity.
↑ What High Syphilis Screening (RPR/VDRL) Means
Reactive RPR/VDRL requires confirmatory treponemal test. If both positive: syphilis (stage depends on symptoms/history). RPR titer correlates with disease activity and guides treatment monitoring.
Common symptoms:
Primary (3 weeks): painless chancre (ulcer) at inoculation site · Secondary (6-8 weeks): diffuse rash (palms and soles), condylomata lata, mucous patches, fever, lymphadenopathy · Latent: asymptomatic (can last years) · Tertiary: neurosyphilis (dementia, tabes dorsalis), cardiovascular (aortitis), gummas
↓ What Low Syphilis Screening (RPR/VDRL) Means
N/A.
Common symptoms:
N/A
Why It Matters
When normal:
Syphilis is completely curable with penicillin
RPR titer monitors treatment response (should decline 4-fold)
Screening prevents late complications (neurosyphilis, cardiovascular syphilis)
Prevents congenital syphilis in pregnancy
Risks if abnormal:
Untreated syphilis: progresses through stages over years
Tertiary syphilis: neurosyphilis, aortitis, gummas
Congenital syphilis: devastating consequences for newborns
Syphilis increases HIV acquisition risk 2-5x
What Can Cause Abnormal Levels?
Treponema pallidum Infection
95% likelySexually transmitted (and vertically from mother to child). The "great imitator"—can mimic many diseases.
Biological False Positive RPR
RPR can be falsely positive in pregnancy, lupus (APS), IV drug use, other infections, and elderly. Always confirm with treponemal test.
What You Can Do
Screen all pregnant women at first prenatal visit
Impact: Prevents congenital syphilis \u00B7 Timeline: First trimester
Screen sexually active individuals at risk annually
Impact: Early detection prevents complications and transmission \u00B7 Timeline: Annual
If lifestyle changes aren't enough:
If RPR reactive: confirmatory treponemal test
Impact: Distinguishes true syphilis from biological false positive \u00B7 Timeline: Immediate
Stage the disease: primary (chancre), secondary (rash), latent, tertiary
Impact: Treatment duration depends on stage \u00B7 Timeline: At diagnosis
Recommended retest: RPR titer q3-6 months post-treatment until appropriate decline confirmed
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