Widal test is used for the diagnosis of:

Explanation

Widal test (developed by G.F.I Widal) is an agglutination test for the presence of antibodies against the Salmonella organism that causes typhoid fever. It is used to diagnose the presence of the disease in a patient. If the patient has been exposed to Salmonella bacteria and has developed antibodies against them, a reaction called agglutination occurs. Agglutination causes the clumping together of the bacterial antigens and antibodies in the test solution, which is visible to the laboratory technician.