Syphilis Serology Interpreter (Traditional and Reverse Sequence)
Syphilis serology interpreter for both CDC testing sequences (CDC 2024 laboratory recommendations).
Open the tool → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Testing sequence
- Reverse sequence: treponemal immunoassay (EIA/CIA) first
- Treponemal test result
- Reactive
- Nontreponemal test result
- Nonreactive
- Second, different treponemal test
- Not done yet
Result: A reactive EIA with a nonreactive RPR is discordant, not a false positive, until a TP-PA is back.
The tool opens with these values already filled in. Replace them with your own.
What you enter
- Testing sequence
- Treponemal test result
- Nontreponemal test result (RPR or VDRL)
- Second, different treponemal test (TP-PA)
- Current nontreponemal titer, the number after 1:
- Prior nontreponemal titer, the number after 1:
- Prior titer from the same nontreponemal test
How this is calculated
Papp JR, Park IU, Fakile Y, Pereira L, Pillay A, Bolan GA. CDC Laboratory Recommendations for Syphilis Testing, United States, 2024. MMWR Recomm Rep. 2024;73(1):1-32. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.