[Serologic markers used for hepatitis B surveillance in Togo: status report and action proposals]

The hepatitis B surface antigen (HBsAg) is the only marker used for diagnosis and follow-up of hepatitis B infection in Togo. The purpose of this study was to evaluate the use of HBsAg testing for follow-up of hepatitis B infection. This study was conducted in 230 patients referred to the National Institute of Hygiene for HBsAg testing. In all cases the requested test was performed and the request and results were evaluated.
Results: The study group included 159 women (69%) and 71 men (31%). The overall prevalence of HBsAg was 10.87%. Prevalence was higher in men than in women. Highest prevalence rates were observed in the age groups 20 to 50, which corresponds to the peak period of sexual activity. The indication for testing was often not clearly specified by Laboratory engineers (85.71%), Clinical officers (73.68%) and physicians (61.24%). When mentioned, the indication was suspicion of hepatitis B (20.87%), work-up for pregnancy (8.70%), testing prior to vaccination (8.26%) and surveillance of an infected patient (1.30%). The prevalence of HBsAg was 0.00% in prevaccination tests, 5% in pregnancy workup tests, and 10.42% in hepatitis B suspicion tests. Test results were negative in one infected patient referred for follow-up. None of the patients with positive results returned for therapeutic follow-up testing and no marker other than HBsAg was requested regardless the indication.
Conclusion: the laboratory of serology is under-used for hepatitis B surveillance. Hepatitis B follow-up using antigen HBsAg alone is inadequate and the equipment required for testing other markers is the same.