Question

What is the approximate incubation period in procedure of Widal Test for testing typhoid?

• A. 15 min at 37$^\circ$C
• B. 30 min at 37$^\circ$C
• C. 60 min at 35$^\circ$C
• D. 30 min at 35$^\circ$C

Hint:

Widal test → 30 min at 37$^\circ$C is the standard incubation for antigen-antibody reaction.

Answer 1

The Correct Option is B

Step 1: Understanding Widal test.
Widal test is a serological test used for diagnosis of typhoid fever caused by Salmonella typhi.
It detects agglutinating antibodies against O (somatic) and H (flagellar) antigens of Salmonella.
Step 2: Principle of the test.
The test is based on antigen-antibody reaction which leads to visible agglutination when patient serum is mixed with antigen suspensions.
Step 3: Incubation period.
For proper antigen-antibody reaction, the mixture is incubated at 37$^\circ$C for about 30 minutes.
This is considered the standard and widely accepted procedure.
Step 4: Conclusion.
Therefore, the approximate incubation period for Widal test is 30 min at 37$^\circ$C.