Question: how is widal test done?
Answer: When the Widal test is performed in a test tube, it is called Tube agglutination and when it is carried out on a slide, it is called Slide agglutination. Widal test by Tube agglutination is recommended over the latter. The antigens used in the test are “H” and “O” antigens of S. typhi and “H” antigen of S.