WIDAL

Overview

Widal Test is an agglutination test which detects the presence of serum agglutinins (H and O) in patients serum with typhoid and paratyphoid fever.The Widal test is the reliable and can be of value in the diagnosis of typhoid fevers in endemic areas.Salmonella antibody starts appearing in serum at the end of first week and rise sharply during the 3rd week of endemic fever. In acute typhoid fever, O agglutinins can usually be detected 6-8 days after the onset of fever and H agglutinins after 10-12 days. It is preferable to test two specimens of sera at an interval of 7 to 10 days to demonstrate a rising antibody titre.