WIDAL TEST AND ITS MEDICAL SIGNIFICANCE IN DIAGNOSIS Authors: Batool Mutar Mahdi
ABSTRACT
Background: Febrile condition is a common disease caused by different pathogens. The
most common microorganism that causes it is Salmonella typhi and Salmonella parartyphi.
The single Widal agglutination test rather than blood culture or other cultures is commonly
used in diagnose typhoid fever.
Aim of the study: To evaluate the medical significance and value of a single Widal test
result in diagnosis febrile typhoid fever patients.
Material and methods: It is a retrospective study on febrile patients to diagnose typhoid
fever and 100 patients were enrolled in the study. Blood sample were collected from the
patients and tested for qualitative Widal slide agglutination test for confirmation of
thedisease. This test is used for detection the presence of anti Salmonella typhi O and H
antibodies, anti Salmonella paratyphi A (O and H) antibodies, anti Salmonella paratyphi B
(O and H) antibodies in the patients’ serum.
Results: Antibodies against S typhi O antigen were 72/100 (72%), and to H antigens was
64/100 (64%). Regarding S paratyphi A, the reactive O antigen was 34/100 (34%) and H
antigen was 16/100 (16%) while S paratyphi O antigen was 23/100 (23%) and H was 14/100
(14%).Among those patients who had positive agglutination reaction for S typhi results, 22
(30.55%) had titer of 1:360 for O antigen and 37 (57.81%) had titer of 1:40 of H antigen of S
typhi. Conclusions: Single Widal agglutination test is used as diagnosis of Typhoid fever by
interpretation of both O and H antigen and the cut-off titer in Iraq was 160 because it’s
endemic in this area.
Keywords: Widal, agglutination, typhoid, Salmonella typhi and Salmonella parartyphi
