Objective: Evaluate the performance of a point-of- care syphilis test when used in urban Bolivian maternity hospitals.
Methods: We tested 8900 pregnant women for syphilis using Abbott's Determine Syphilis TP point-of-care (POC) test and RPR in the laboratory of four large urban maternity hospitals where national statistics reported a syphilis prevalence of at least 3%. Sera were stored and transferred to the national reference laboratory (INLASA) where RPR testing was repeated. When the reference laboratory staff observed a positive RPR result, TPPA was performed to confirm these findings. We calculated test performance characteristics for the POC test and hospital RPR using RPR performed at the reference laboratory confirmed by TPPA as the reference standard. Participants received treatment during their initial visit based on the POC test results.
Findings: The sensitivity, specificity, negative predictive value and positive predictive values of the POC syphilis test were: 91.8% (95% confidence intervals (CI): 88.4-94.5), 98.5% (95% CI: 98.2-98.8), 71.0% (95% CI: 66.6-75.2), 99.7% (95% CI: 99.5-99.8), respectively. The RPR values were 75.7% (95% CI: 70.8-80.2), 99.0% (95% CI: 98.9-99.3), 76.9% (95% CI: 72.0-81.3), and 99.0% (95% CI: 98.8-99.2).
Conclusion: The Abbott Determine Syphilis TP test proved to be more sensitive than routine RPR and had comparable specificity. Point-of-care testing may be a simple way to expand syphilis screening to clinics with no laboratory facilities, improve case detection, and facilitate treatment delivery.