Widal agglutination test - 100 years later: still plagued by controversy.

We review the significance of the Widal agglutination test in the diagnosis of typhoid fever. Over 100 years since its introduction as a serologic means of detecting the presence of typhoid fever, the Widal test continues to be plagued with controversies involving the quality of the antigens used and interpretation of the result, particularly in endemic areas. Areas of concern with clinical and laboratory significance discussed in this review include: the techniques of test performance, interpretation of results, limitation of the value of the test results in endemic typhoid areas, the quality of the antigens used, and alternative diagnostic tests.