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Relying on Widal test alone could lead to over diagnosis of typhoid fever: Findings from a records review of febrile patients at Damphu Hospital, Bhutan, 2011-2012

Introduction: The Widal test is widely used in hospitals in Bhutan for diagnosis of typhoid fever. The right test with high sensitivity and specificity supplements clinical judgement and contributes to correct diagnosis of disease. This study focuses on the contribution of the Widal test in the diagnosis of typhoid fever.
Methods: Data was collected from records of patients who presented to Damphu hospital from March 2011 to June 2012 with clinical suspicion of typhoid fever. Blood samples were collected from patients and tested at Damphu Hospital, Tsirang and the Royal Centre for Disease Control, Thimphu. Seventy records were used for the study.
Results: There was no growth of Salmonella typhi on blood cultures from patients who had tested positive in the Widal test. There were 20 (28.57%) samples which tested positive for scrub typhus; among these Widal test was positive in 10 (50%) samples. Thirty-four out of 36 (94.44%) patients had the duration of illness less than seven days and among them, 26 (74.47%) had positive Widal test results.
Conclusion: None of the samples that tested positive by Widal test gave a definite diagnosis of typhoid fever with blood culture. Clinical judgement may be more challenging because patients with other febrile illnesses like Scrub typhus also have positive Widal test result. We conclude that it is best not to rely on the Widal test alone for the diagnosis of typhoid fever and this test should be replaced by more accurate ones.
Keywords: Salmonella typhi; Typhoid fever; Widal test.
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