Widely used diagnostic test for HIV infection

Options

A. Widal test
B. ELISA test
C. Schick test
D. Blotting technique

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the widely used diagnostic test for HIV infection. It provides four options: Vidal test, ELISA test, SHIC test, and blotting technique.

2. **Analyzing the Options**:
- **Vidal Test**: This test is primarily used for diagnosing typhoid fever, not HIV.
- **ELISA Test**: This stands for Enzyme-Linked Immunosorbent Assay. It is a widely used test for detecting antibodies against HIV in a person's blood.
- **SHIC Test**: This test is used to check immunity to diphtheria and is not related to HIV diagnosis.
- **Blotting Technique**: This is often used as a confirmatory test after an initial screening test like ELISA.

3. **Identifying the Correct Answer**: Among the options, the ELISA test is the primary and widely used diagnostic test for HIV infection. It detects the presence of antibodies against the HIV virus.

4. **Understanding the ELISA Test**:
- The ELISA test works by determining if antibodies against HIV are present in the blood.
- If antibodies are present, the result indicates that the person is HIV positive.
- If no antibodies are detected, the person is considered HIV negative.

5. **Confirmatory Testing**: While ELISA is the primary test, if the result is positive, a confirmatory test (often a blotting technique like Western blot) is performed to ensure accuracy.

6. **Final Answer**: The widely used diagnostic test for HIV infection is the **ELISA test**.