Question

A person was suffering from a particular disease, say X. The doctor carried out a test for detection of the disease. He found that the person's blood serum has a lot of antibodies which react with Salmonella Typhi antigens. Identify the disease and the detection test carried out by the doctor.

• A. Typhoid, Widal test
• B. Pneumonia, Widal test
• C. Common cold, Widal Test
• D. Typhoid, Fehling's test

Answer 1

The correct option is A Typhoid, Widal test

Widal test is based on the principle that a patient suffering from typhoid has a lot of antibodies that will react against the antigens of Salmonella Typhi. So we take the blood serum of the patient and add it to a Widal test suspension that contains inactivated preparations of various Salmonella antigens. The antibodies in the patient's serum will bind to the antigens in the suspension and it appears as agglutination or aggregation of antibody-antigen complex. Therefore appearance of agglutination indicates a positive diagnosis for typhoid.