Evaluation of the baseline Widal titres in healthy blood donors of Uttarakhand

Abstract

Introduction: The interpretation of Widal test depends upon the baseline titre which is prevalent amongst healthy individuals in a particular geographical area. Aim and Objective: The aim of this study was to determine the baseline Widal titre of the apparently healthy population of a tertiary care centre of Uttarakhand. Material and Methods: Blood samples were collected from healthy blood donors (n=500) of the age group of 18-60 years, of both the sexes, who attended our blood bank from September 2013 to November 2013 and were analyzed for the presence of Salmonella antibodies by carrying out the Widal tube agglutination test. Results: Of the 500 serum samples which were tested, 255 (51%) serum samples were positive for agglutinins (? 1:20) and 245 were negative. The most frequently recorded titre of the reactive sera was 1:40 for the anti-O antibodies and 1:80 for the anti-H antibodies for Salmonella enterica serotype typhi and this was the baseline titre. While the baseline titre of the ‘H’ agglutinins of Salmonella enterica serotype paratyphi A was 1:20 and of paratyphi B was also1:20. Conclusions: Based on the results of our study, it has been recommended that the significant titre of 1:80 for the anti-O antibodies and of 1:160 for the anti-H antibodies may be considered as diagnostic for enteric fever in the region of Uttarakhand, India.