Newer Syphilis Reverse Algorithm 


The advent of newer, faster 

treponemal antibody tests have 

allowed high-throughput of 

sensitive and specific trep. tests 

as the first step in the algorithm.


Newer Trep (+) 

(chemiluminescent/ 

ELISA trep antibody) 

Reflex to non-Trep. 

(VDRL or RPR) 

Non-trep tests look for patient antibodies 

that interact with cardiolipin, derived from 

ox hearts. This is a less specific marker 

of inflammation caused by syphilis but 

also other conditions. The titre is also 

quantitative and may be trended. 


For the small subset of patients with 

discordant trep and non-trep, the 

slower, more labor-intensive treponemal 

test (TPPA) can be performed. If (+) for 

new and old trep test, but (-) for anti- 

cardiolipin (ox heart), consider untreated 

chronic infection vs. previously treated 

infection vs. very early infection. 


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