Background: Widal test is the most widely used laboratory investigation
for diagnosis of typhoid. However, the test interpretation remains controversial in the
context of endemic regions such as Bangladesh, as agglutination occurs at varied 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, diagnosis and
Objective: We aimed to assess the normal range of baseline titre for Anti TO, TH,
AO, AH, BO agglutinins among healthy population in an endemic country with a
view to guide the researchers and the clinicians, facilitating further investigation on
updating cut off points of single Widal test for screening and diagnosis of typhoid
fever in the context of Bangladesh.
Methods: A cross-sectional study was carried out in Mymensingh Medical College,
Bangladesh on 2925 male immigration applicants. A single blood sample was collected
for Widal test and interpreted using standard guidelines.
Results: The highest baseline titer for Anti TO, TH, AO, AH, BO agglutinins among
95% of the healthy participants was found to be 1:80 for each respectively. A titre of
1: 40 was observed for BH antigen.
Conclusion: In case of singular Widal test, baseline values for the normal range
was found to be 1:20 - 1:80 for all the antigens (TO, TH, AO, AH, BO, BH), except
BH, for which it was 1:20-1:40. Further studies, inclusive of other sociodemographic
groups and positive controls are required to determine the updated
cut off values.