Is routine antenatal venereal disease research laboratory test still justified? Nigerian experience

Objective: To determine the seroreactivity of pregnant women to syphilis in order to justify the need for routine antenatal syphilis screening.

Methods: A multicenter retrospective analysis of routine antenatal venereal disease research laboratory (VDRL) test results between 1 September 2010 and 31 August 2012 at three specialist care hospitals in south-east Nigeria was done. A reactive VDRL result is subjected for confirmation using Treponema pallidum hemagglutination assay test. Analysis was by Epi Info 2008 version 3.5.1 and Stata/IC version 10.

Results: Adequate records were available regarding 2,156 patients and were thus reviewed. The mean age of the women was 27.4 years (±3.34), and mean gestational age was 26.4 weeks (±6.36). Only 15 cases (0.70%) were seropositive to VDRL. Confirmatory T. pallidum hemagglutination assay was positive in 4 of the 15 cases, giving an overall prevalence of 0.19% and a false-positive rate of 73.3%. There was no significant difference in the prevalence of syphilis in relation to maternal age and parity (P>0.05).

Conclusion: While the prevalence of syphilis is extremely low in the antenatal care population at the three specialist care hospitals in south-east Nigeria, false-positive rate is high and prevalence did not significantly vary with maternal age or parity. Because syphilis is still a serious but preventable and curable disease, screening with VDRL alone, without confirmatory tests may not be justified. Because of the increase in the demand for evidence-based medicine and litigation encountered in medical practice, we may advocate that confirmatory test for syphilis is introduced in routine antenatal testing to reduce the problem of false positives. The government should increase the health budget that will include free routine antenatal testing including the T. pallidum hemagglutination assay.