Baseline Widal titre among healthy adult males from the greater Mymensingh division of Bangladesh

Widal agglutination test is arguably the most widely used laboratory investigation for diagnosis of Typhoid, especially in developing countries where blood culture is often inaccessible. However, the interpretation of the test still remains a controversial topic particularly in the context of endemic regions such as Bangladesh, as agglutination test is often found positive in varied and higher titrations among a large percentage of healthy population. Paired Widal tests are often not feasible, hence single unpaired test has to be used for screening and diagnosis. Even specific chemotherapy is administered frequently based on single Widal test. Therefore it is very important to establish baseline value of Widal test and re-evaluate in regular intervals to ensure standard cutoff points are as accurate and updated as possible in particular demographics Objective: The study aimed at investigating the normal range of baseline titre for Anti TO, TH, AO, AH, BO agglutinins among healthy participants, with a view to inform policy makers and clinicians on the updated cut off values for screening and diagnosis of typhoid fever in the context of Bangladesh.

METHODS:

A cross sectional study was carried out in the Department of Microbiology of Mymensing Medical College, Mymensingh, Bangladesh in two time points, one was from February 2013 to September2013 and another was from March to April, 2015 . A total of 3161 adult (18-45 years) male job seekers to Malaysia attending for health check up were invited to the study and out of them 2925 could be finally enrolled. A single blood sample was collected and Widal test was carried out according to kit manufacturer’s instructions and interpreted using standard guidelines.

RESULTS:

The significant baseline titers for Anti TO, TH, AO, AH, BO agglutinins among the participants were found to be 1:80 for each respectively. A titer of 1: 40 was observed for BH antigen Conclusion: In case of singular Widal test, base line values for normal range should be revised and set 1:80 for all the antigens (TO, TH, AO, AH, BO, BH), except BH, for which it should be 1:40. Further studies in different geological and demographic groups are required to ascertain the use of right context and cut off values for screening and diagnostic purposes.