The chemical test that is used for diagnosis of typhoid is

Options

A. ELISA - Test
B. ESR - Test
C. PCR - Test
D. Widal - Test

Answer

To solve the question regarding the chemical test used for the diagnosis of typhoid, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Disease**: Understand that typhoid fever is caused by the bacteria *Salmonella typhi* and *Salmonella paratyphi*.

2. **Know the Tests Available**: The options provided for the tests are:
- A) ELISA test
- B) ESR test
- C) PCR test
- D) Vidal test

3. **Evaluate Each Test**:
- **ELISA test**: This test is primarily used for diagnosing infections like AIDS and is not specific for typhoid.
- **ESR test**: This test measures the sedimentation rate of red blood cells and is not specific for diagnosing typhoid.
- **PCR test**: This test is used to amplify DNA and can be used for various infections but is not a standard test for typhoid.
- **Vidal test**: This is a serological test specifically designed to detect antibodies against *Salmonella* in the patient's serum, indicating a typhoid infection.

4. **Select the Correct Answer**: Based on the evaluations, the Vidal test is the correct chemical test used for the diagnosis of typhoid.

### Final Answer:
The chemical test that is used for the diagnosis of typhoid is the **Vidal test**.

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