The confirmatory test used to diagnose AIDS is:

Options

A. ESR
B. Widal
C. ELISA
D. Western Blot

Answer

**Step-by-Step Solution:**

1. **Understand the Question**: The question is asking for the confirmatory test used to diagnose AIDS. AIDS is caused by the Human Immunodeficiency Virus (HIV).

2. **Review the Options**: The options provided are:
- A) ESR (Erythrocyte Sedimentation Rate)
- B) Vidal test
- C) ELISA test
- D) Western blot test

3. **Evaluate Each Option**:
- **Option A: ESR**: This test measures the rate at which red blood cells settle in a tube. It is used to detect inflammation but is not specific for AIDS. Therefore, this option is incorrect.
- **Option B: Vidal Test**: This test is used to diagnose typhoid fever. It does not relate to HIV/AIDS diagnosis. Thus, this option is also incorrect.
- **Option C: ELISA Test**: The ELISA (Enzyme-Linked Immunosorbent Assay) test is used to screen for HIV antibodies. However, it is not a confirmatory test. If the ELISA test is positive, further testing is required. Therefore, this option is incorrect.
- **Option D: Western Blot Test**: This is a confirmatory test that is performed after a positive ELISA test. It detects specific HIV antibodies in the blood and is considered highly accurate for confirming HIV infection. Thus, this option is correct.

4. **Conclusion**: The confirmatory test used to diagnose AIDS is the **Western blot test**.

**Final Answer**: D) Western blot test

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