USE OF A POINT OF CARE TEST DEVICE TO DETECT SYPHILIS IN A STD CLINIC

Background Diagnosis of syphilis is problematic and an accurate rapid point of care (POC) test could be useful in busy STD clinics. There are no FDA Cleared POC tests for Syphilis serology in the USA. Objective To determine the performance of a new, rapid point of care (POC) test, Syph-Check, which is not yet FDA cleared, for the serological diagnosis of Treponema pallidum in female and male STD patients. Methods Men and women >18 yr visiting the Baltimore City Health Department STD clinic were consented to enrol in a trial to determine the accuracy of a new, innovative POC test for syphilis (Veda, manufactured in France) that used a cassette format to test syphilis serology. The Syph-Check One-Step Syphilis test is a point of care, rapid immunoassay screening test for qualitative detection of IgG and IgM antibodies to Treponema pallidum in finger stick blood, plasma, and serum. This product can be used as an initial screening test or as a confirmatory diagnostic test, but is not FDA cleared for use in screening blood or plasma donors. The assay was performed in the STD clinic, required only 20 min to perform, and required no instrumentation. RPR and TPPA tests were performed to determine the sensitivity and specificity of the Syph-Check POC test. Results 194 men and 205 women were enrolled. Of the 399 samples tested, 33 were positive and 366 were negative by the Syph-Check. There were 14 positives and 385 negatives by RPR confirmatory testing. Overall sensitivity compared to RPR testing was 85.7% (95% CI 60.3% to 97.5%) and specificity was 94.5% (95% CI 91.9% to 96.5%). There were 32 positives and 367 negatives by TPPA confirmatory testing. Overall sensitivity compared to TPPA was 43.8% (95% CI 27.5% to 61.1%) and specificity was 94.8% (95% CI 92.2% to 96.8%). Conclusions The Syph-Check POC test was moderately accurate compared to the RPR test, but not as sensitive compared to TPPA. A more accurate POC test for syphilis could be useful for clinicians to test clinic patients and provide immediate screening results for syphilis to patients during an office or clinic visit.