Question

Which of the following is the best technique for detecting HIV:

• A. Widal test
• B. Real-time PCR
• C. Polymerase chain reaction
• D. Reverse transcriptase-PCR

Answer 1

The Correct Option is D

Step 1: Understanding the Concept.
HIV belongs to a group of viruses called retroviruses, which carry RNA as their genetic material instead of DNA. Any detection method built around amplifying DNA needs an extra step to work with this kind of virus.

Step 2: Key Approach.
Match each listed test to what it actually detects, bacteria, DNA, or RNA, and see which one is built to handle an RNA virus.

Step 3: Detailed Explanation.
The Widal test is for typhoid, caused by bacteria, so it is unrelated to viral testing altogether.
Ordinary PCR and real-time PCR both amplify DNA templates, and HIV does not naturally have a DNA genome inside the virus particle.
Reverse transcriptase-PCR solves this gap by using the enzyme reverse transcriptase to copy the viral RNA into DNA first, after which standard PCR amplification and real-time detection can proceed.
This combined process gives high sensitivity and can pick up infection early, before the body has built up detectable antibodies.

Step 4: Final Answer.
The best technique for detecting HIV is reverse transcriptase-PCR.