Does performance and operational superiority of point-of-care test make it the investigation of choice in confirming syphilis?

BACKGROUND

According to the World Health Organization, 6 million cases of syphilis occur every year. Serological tests for syphilis form the mainstay of diagnosis for syphilis. We evaluated the performance of point-of-care test (POCT) against other specific treponemal test for confirming the diagnosis of syphilis.

MATERIALS AND METHODS

Does performance and operational superiority of POCT make it the investigation of choice in confirming syphilis? Retrospectively, data were analyzed of 599 serum samples from Apex Regional sexually transmitted disease centre, Safdarjung Hospital, New Delhi, received for testing by syphilis treponemal assays (both nontreponemal reactive and nonreactive). These samples underwent treponemal testing for syphilis by the hemagglutination (TPHA), fluorescent treponemal antibody absorption test (FTA-ABS), and POCT. Performance characteristics (sensitivity, specificity, positive predictive value [PPV], negative predictive value [NPV], and diagnostic accuracy), and operational characteristics of POCT and TPHA were evaluated against the gold standard FTA-ABS.

RESULTS

A total of 599 samples were evaluated, of which 61.76% were positive by FTA-ABS. On analysis, the sensitivity was 91.08% and 91.89%, specificity was 89.08% and 87.34%, PPV was 93.09% and 92.14%, NPV was 86.08% and 86.96%, and diagnostic accuracy was 90.32% and 90.15% for POCT and TPHA, respectively. The lower cost, shorter turnaround time, lesser infrastructure and workforce need, and easy availability make the POCT operationally superior to TPHA.

CONCLUSION

Owing to its operational superiority and higher specificity POCT can replace TPHA for confirming the diagnosis of Syphilis. POCT are affordable, equipment free, have room temperature storage, and yield result within 15 minutes, enabling same day testing and treatment. It can be used in a resource limited setting, for community setup or even self-testing.