This review concluded that immunochromatographic strip testing may be useful in widening the scope of syphilis screening in low-income countries, but must be accompanied by appropriate treatment and partner services in order to fully realise potential benefits. Despite some methodological limitations, these conclusions are appropriately cautious and likely to be reliable.

To assess the accuracy of immunochromatographic strip tests in screening for syphilis infection.

MEDLINE, EMBASE, and databases from the International AIDS Society and the American Society for Microbiology were searched to January 2010, without language or date restrictions. Search terms were reported. The website of the WHO Sexually Transmitted Diseases Diagnostic Initiative was reviewed for further studies.

Studies of immunochromatographic strip testing for syphilis, using finger-stick blood or serum samples collected at antenatal or sexually transmitted infection clinics were eligible for inclusion. Included studies had to apply a treponemal reference standard. Eligible studies were required to report the total number of patients, and positive and negative tests results, and tests had to meet the ASSURED (affordable, sensitive, specific and user friendly) criteria. Studies of archived samples were excluded.

Although all included studies used at least a treponemal test as the reference standard, the authors reported that five studies used a combination of treponemal and non-treponemal tests. TMost included studies were conducted in in urban health centres in low-income or middle-income countries. Approximately half of the studies were based in antenatal clinical and half in sexually transmitted infection clinics. Three studies (20%) included patients infected with HIV. Eight different commercial tests for syphilis were used by included studies.

Studies were independently assessed for inclusion by two reviewers and disagreements were resolved by consultation with a third reviewer. Spanish studies were assessed by a research assistant proficient in Spanish and checked by one of the reviewers.

The authors did not state that they assessed methodological quality.

Data to populate 2x2 contingency tables were independently extracted by two reviewers. Study investigators were contacted if further data were needed. Sensitivity, specificity and diagnostic odds ratio (DOR), with 95% confidence intervals (CIs), were calculated for each data set.

Studies were combined using a narrative synthesis. For individual included studies, sensitivity, specificity and diagnostic odds ratio estimates were presented in forest plots; median and interquartile range (IQR) values were reported. Results were also plotted in receiver operating characteristic (ROC) space. . Positive values were estimated on the basis of median test characteristics at various levels of syphilis prevalence.

Between study heterogeneity was assessed using the χ² test.

Funnel plots were generated to allow visual inspection for publication bias; tests for rank correlation (Begg’s test) and for regression asymmetry (Egger’s test) were analysed for asymmetry.

Fifteen studies reporting 23,055 test results were included in the review. All studies were retrospective cross-sectional surveys.

The median immunochromatographic strip syphilis test sensitivity was 0.86 (IQR 0.75 to 0.94) and the median specificity was 0.99 (IQR 0.98 to 0.99); values were similar in antenatal and sexually transmitted infection clinics. The median diagnostic odds ratio was 737 (IQR 210 to 1,443).

The immunochromatographic strip syphilis tests showed a greater than 80% positive predictive value of syphilis when the syphilis prevalence was greater than 0.3%.

There was evidence of significant between study heterogeneity, but there was no evidence of publication bias.

Although immunochromatographic strip syphilis testing may not be a panacea for inadequate syphilis screening in many low-income countries, the new tests had the potential to widen the breadth and depth of screening efforts. Syphilis testing must be reliably followed by appropriate treatment and partner services to translate the benefits of immunochromatographic strip syphilis testing into effective syphilis prevention. Immunochromatographic strip syphilis testing will be an important first step in this process of more robust syphilis control.

The review addressed a clearly stated research question, defined by appropriate inclusion criteria. A number of sources were searched for relevant studies, without language restrictions. Measures to minimise error and/or bias were taken for the selection of studies and data extraction.

No assessment of the methodological quality of included studies was reported, so it was not possible to judge the potential impact of primary study quality on the reliability of the review findings. The choice of a narrative synthesis was reasonable, given the apparent heterogeneity of included studies.

Overall, the authors' conclusions were appropriately cautious and are likely to be reliable.

Practice: The authors made no specific recommendations for practice.

Research: The authors stated that further research evaluating immunochromatographic strip syphilis tests among primary syphilis cases and among patients infected with HIV will be essential for the effective roll-out of syphilis screening programmes.

The China Syphilis Working Group; the UNC Fogarty AIDS International Research and Training Program (NIH FIC D43 TW01039); the UNC Social Science Research on HIV/AIDS in China (NIH NICHDR24 HD056670-01); the UNC Center for AIDS Research; the UNC STI Cooperative Grant, the WHO Rapid Syphilis Test Project (UNICEF/UNDP/ World Bank/WHO A70577); the US NIH Fogarty International Center International Clinical Fellowship; the Harvard Initiative for Global Health; Burroughs Wellcome Fund/American Society of Tropical Medicine and Hygiene Wellcome Postdoctoral Fellowship in Tropical Infectious Diseases.

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.