Reagent used in ELISA test is

Options

A. Endonuclease
B. Polymerase
C. Ligase
D. Peroxidase

Answer

To answer the question regarding the reagent used in the ELISA test, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the ELISA Test**:
- ELISA (Enzyme-Linked Immunosorbent Assay) is a biochemical technique used to detect the presence of antibodies or antigens in a sample. It is commonly used for diagnosing diseases and measuring immune responses.

2. **Identifying the Components**:
- The key components of an ELISA test include the antigen, antibody, and an enzyme-linked reagent. The enzyme is crucial for the detection process.

3. **Reagents in ELISA**:
- In the context of ELISA, the main reagent used is an enzyme that is linked to the antibody. This enzyme catalyzes a reaction that produces a measurable signal, usually a color change.

4. **Common Enzymes Used**:
- The most commonly used enzyme in ELISA tests is **peroxidase**. This enzyme reacts with a substrate to produce a color change, indicating the presence of the target antigen or antibody.

5. **Conclusion**:
- Therefore, the reagent used in the ELISA test is **peroxidase**.

### Final Answer:
The reagent used in the ELISA test is **peroxidase**.

---