Widal Test: An Age Old Conflict of Merits & Pitfalls

The Widal agglutination test was developed by F. Widal in 1896 to help in diagnosis of typhoid. These days, widal tests can be replaced by a variety of other rapid tests. Unfortunately in some developing countries, the situation is quite different and the widal test seems to be the sole laboratory method used to diagnose typhoid fever in suspected cases. The slide widal test that has the advantage of being highly practicable and low cost being used more followed by the tube widal test that requires at least overnight incubation.

Diagnosis of typhoid fever based on serology alone is frequently inaccurate. The test has significant cross-reactivity with other infectious agents, which can lead to false-positive results and an overdiagnosis of typhoid fever accompanied by misuse of the preferred first-line medication, which has caused resistant strains of S typhi to proliferate.

Consequently, the widal test should only be used in circumstances where no other supportive or confirmatory test, like a positive culture, is available. Whenever the clinical picture is unclear, a quick, precise, sensitive and accurate test should be performed to distinguish between typhoidal and non-typhoidal febrile fever.

Since the widal test is frequently employed in laboratories with limited resources, the results should always be interpreted in light of clinical data if it is to be utilized at all. Despite a century of debate about merits and demerits, the widal test continues to be regarded as a reliable assessment tool. However, in order to provide accurate and timely diagnosis, it is now necessary to replace the test in a primary care physician's practice with complementary rapid diagnostic assays.

References 

1. Ley et al. Evaluation of the Widal tube agglutination test for the diagnosis of typhoid fever among children admitted to a rural hospital in Tanzania and a comparison with previous studies. BMC Infectious Diseases 2010;10:180.

2. Gaikwad UN, Rajurkar M. Diagnostic efficacy of Widal slide agglutination test against Widal tube agglutination test in enteric fever. Int J Med Public Health 2014;4:227-30.

3. Gemechu Ameya, Edemew Atalel, Berhanu Kebede & Bethel Yohannes. Comparative study of Widal test against stool culture for typhoid fever suspected cases in southern Ethiopia, Pathology and Laboratory Medicine International 2017;9:1-7.

4. Saini V, Duggal N. Comparison of rapid tests (antigen vs. antibody) for the diagnosis of typhoid in the first and second weeks of fever. J Family Med Prim Care 2022;11:3730‑4.

5. Veena Maheshwari et al. A Comparative Evaluation of Different Diagnostic Modalities in the Diagnosis of Typhoid Fever Using a Composite Reference Standard: A Tertiary Hospital Based Study in Central India. Journal of Clinical and Diagnostic Research. 2016 Oct, Vol-10(10): DC01-DC04.

6. Olopenia, King. Widal agglutination test- 100 years later: still plagued by controversy. Postgrad Med J 2000;76(892):80-84.