The Centers for Disease Control and Prevention (CDC) released what the agency says are the first comprehensive recommendations on laboratory testing for syphilis. The extensive guidance covers laboratory-based tests, point-of-care tests (POC), processing of samples, and reporting of test results. In general, for symptomatic patients, nontreponemal tests are recommended for laboratory screening. Treponemal tests are used to validate nontreponemal results and to diagnose early syphilis infections not detectable by nontreponemal tests. Additionally, CDC notes that treponemal antibodies can indicate a past syphilis infection and are present for life. Sustained growth in the number of syphilis cases has led to an epidemic with cases increasing from 5,979 reported in 2000, to 133,945 in 2020, to 207,255 in 2022.
The future of testing: Timely diagnosis is an important factor for improving patient outcomes, but non laboratory POC tests for syphilis are still in their infancy in the United States. More study is needed to determine their performance and how to best apply algorithms for patient populations.