Distribution of Salmonella Typhi Antibodies in the Sera of Healthy Blood Donors at Kenyatta National Hospital.
Online Journal of Medicine and Medical Science Research. 3(3):19-23. Abstract
Typhoid fever is widespread in Kenya. Widal test interpretation requires knowledge of the baseline titres amongst healthy population. These normal agglutinin titres vary depending on the degree to which typhoid fever is endemic in each area, a factor which may change over time. It has been a decade since Widal titres in apparently healthy population has been assessed. Furthermore, no baseline Widal titres have been assessed in blood donors. The method applied was a cross sectional descriptive analysis whereby voluntary and healthy blood donors at Kenyatta National Hospital Blood Transfusion Unit were consecutively sampled and screened for Salmonella Typhi agglutinin titres using the Widal test from October 2012 to November 2012. Demographic and focused medical history was obtained by use of structured pretested questionnaires. Blood sample was taken for assessment of Widal titres. Among the 353 serum specimen tested, 75 (21.25%) sera were found to be positive for the Widal test and 278 (78.75%) were negative. The most frequently recorded titre of the reactive sera was 1: 40 for both the anti-O antibodies and the anti-H antibodies which occurred in 49% and 44% of the reactive sera respectively. About 20% of healthy blood donors had a positive Widal screening test, with 50% constituting a baseline titre of 1: 40 for both O and H antigens. A significant proportion of blood donors had titres ≥1: 80. Hence, the researchers recommend the cut off titres of ≥ 1:80 for diagnosis of typhoid fever with the appropriate clinical features.