Rapid / Point of Care Testing for Syphilis: Canadian and International Perspectives
• Syphilis remains a global health problem with an estimated 12 million people infected annually.
• Rapid / point of care testing (RPOCT) may be defined as a “Point of Care Test” carried out in a clinical or non-clinical setting for which the result is available without testing at a laboratory and “Rapidly” enough (with test results typically available in < 20 minutes) to affect immediate patient management.
• More than a dozen commercially available syphilis RPOCT are available internationally.
• Immunochromatographic strip (ICS) tests, a type of treponemal test, have been widely evaluated using both whole blood and sera; the median reported sensitivity of ICS tests is 0.86 (interquartile range [IQR] 0.75-0.94) with median specificity of 0.99 (IQR 0.98-0.99).
• Antenatal cost-effectiveness of RPOCT shows that the ICS TT tests are cost-effective for the detection of maternal syphilis in low resource settings.
• Some of the inherent challenges of syphilis testing also exist with syphilis RPOCT. For example, because positive treponemal RPOCT may indicate new or old infections, a quantitative non-treponemal test is often helpful. No commercially available non-treponemal RPOCT is available as a single test at this time but two dual tests are commercially available.
• In Canada due to the low prevalence of infectious syphilis for many years, widespread availability of syphilis testing at laboratories and lack of a licensed syphilis RPOCT, there is no routinely used RPOCT for syphilis.
• In developed nations such as Canada, RPOCT for syphilis is potentially of greatest benefit in areas experiencing a resurgence of infectious syphilis and in hard-to-reach populations.