Widal Card

Widal test is a serological test used for the diagnosis of enteric fever or typhoid fever. It measures agglutinating serum antibodies level produced against the O (somatic) and H (flagellar) antigen of Salmonella Typhi and Paratyphi A, B, and C. The test was developed by Greembaum and Widal in 1896. The Widal test is positive after the tenth day of the disease and may be falsely positive if an individual previously received a typhoid vaccine. dual previously received a typhoid vaccine.