Abstract

Objectives: We undertook a prospective evaluation of the Qualpro Syphicheck-WB rapid syphilis test to measure its diagnostic performance and utility as a point-of-care (POC) screening test among female sex workers (FSWs) in Bangalore, India.

Methods: From August 2008 – May 2009, FSWs without a laboratory-confirmed history of syphilis attending STI clinics in Bangalore underwent POC syphilis screening using finger-prick whole blood, with onsite treatment if indicated. Serum samples were collected for local laboratory offsite RPR testing and reference laboratory RPR, TPHA, and rapid syphilis testing. FSWs who participated in standard offsite RPR screening from August 2007 – May 2008 in the same clinics formed the comparison group for treatment coverage.

Results: Of the 1,617 women who underwent POC syphilis testing, 7.4% had laboratory evidence of active syphilis with reactive RPR and TPHA, and 3.7% had an RPR titre ≥1:8. Compared to the reference RPR and TPHA, the sensitivity and specificity of the POC syphilis test were 70.8% (95% CI: 62.7-79.0) and 97.8% (95% CI: 97.1-98.5). Because of the low rate of women returning for their test results after offsite RPR screening, the proportion of women with active syphilis who were appropriately treated rose from 44.8% to 68.3% with the use of POC syphilis screening (p=0.003).

Conclusion: The Syphicheck-WB test utilizing finger-prick whole blood has relatively low sensitivity in detecting active syphilis. However, among hard-to-reach populations who may not return for follow-up treatment, POC screening with this assay could still confer an advantage over offsite RPR testing with respect to treatment coverage.