Question

Widal test is used to diagnose:

• A. Typhoid
• B. Malaria
• C. Pneumonia
• D. Cancer

Hint:

Remember: \[ \text{Widal Test} \rightarrow \text{Typhoid} \] \[ \textit{Salmonella typhi} \rightarrow \text{Typhoid fever} \] A commonly asked NCERT-based fact in CUET, NEET and board examinations.

Answer 1

The Correct Option is A

Step 1: Recall the purpose of the Widal test. The Widal test is a serological test used to detect antibodies against: \[ \textit{Salmonella typhi} \] the bacterium responsible for typhoid fever.

Step 2: Understand what the test detects. The test identifies antibodies against: \[ \text{O antigen} \] and \[ \text{H antigen} \] of Salmonella typhi present in the patient's serum.

Step 3: Evaluate the options.
• Typhoid \(\rightarrow\) Diagnosed using Widal test \(\checkmark\)
• Malaria \(\rightarrow\) Diagnosed by blood smear/rapid antigen test \(\times\)
• Pneumonia \(\rightarrow\) Diagnosed by clinical and laboratory methods \(\times\)
• Cancer \(\rightarrow\) Not diagnosed by Widal test \(\times\) Therefore, \[ \boxed{\text{Typhoid}} \] Hence, the correct answer is: \[ \boxed{\text{(A)}} \]