Confirmatory Treponemal Testing After Positive RPR

Diagnostic Algorithm Following Positive RPR

The Centers for Disease Control and Prevention recommends ordering a treponemal-specific test (TP-PA, FTA-ABS, or treponemal EIA/CIA) to confirm the diagnosis after a positive RPR test 1, 3
A positive treponemal test confirms active syphilis infection or past treated infection, and the stage of syphilis should be determined based on clinical presentation, history, and RPR titer 1, 3

The Centers for Disease Control and Prevention recommends benzathine penicillin G 2.4 million units IM as a single dose for primary, secondary, or early latent syphilis (<1 year duration) 4, 5
For late latent syphilis (>1 year duration or unknown duration), the recommended treatment is benzathine penicillin G 2.4 million units IM weekly for 3 consecutive weeks (total 7.2 million units) 4, 5
For neurosyphilis, ocular syphilis, or otic syphilis, the recommended treatment is aqueous crystalline penicillin G 18-24 million units per day (administered as 3-4 million units IV every 4 hours or continuous infusion) for 10-14 days 5

The Centers for Disease Control and Prevention recommends that all pregnant women be screened for syphilis early in pregnancy, and penicillin is the only therapy with documented efficacy for preventing maternal transmission and treating fetal infection 5, 6

The Centers for Disease Control and Prevention recommends using quantitative nontreponemal tests (RPR or VDRL) to monitor treatment response, and a fourfold decline in titer (two dilutions) represents a clinically significant treatment response 3, 4
For primary and secondary syphilis, a 2-3 tube decline in RPR titer is expected by 6-12 months after treatment 4

The Centers for Disease Control and Prevention advises against treating based solely on a positive RPR without treponemal confirmation, as biological false positives are common 2, 3
Treponemal tests should not be used to monitor treatment response, as they remain positive for life in most patients regardless of treatment 3