Which of the following technique is not used for early diagnosis of disease?

Options

A. Polymerase chain reaction
B. Recombinant DNA technology
C. Enzyme linked immuno sorbent assay
D. Conventional method

Answer

To solve the question "Which of the following techniques is not used for early diagnosis of disease?", we can follow these steps:

### Step 1: Understand the Techniques Listed
We have four techniques to analyze:
1. Polymerase Chain Reaction (PCR)
2. Recombinant DNA Technology
3. Enzyme-Linked Immunosorbent Assay (ELISA)
4. Conventional Methods

### Step 2: Analyze Each Technique
- **Polymerase Chain Reaction (PCR)**: This technique amplifies nucleic acids, allowing for the detection of pathogens even at low concentrations. It is commonly used for early diagnosis, such as detecting HIV in suspected AIDS patients.

- **Recombinant DNA Technology**: This method involves combining DNA from different sources to create new genetic combinations. It can provide precise diagnostic information about genetic diseases, making it useful for early diagnosis.

- **Enzyme-Linked Immunosorbent Assay (ELISA)**: This technique detects the presence of antigens or antibodies in the patient’s serum, which can indicate an infection. ELISA is widely used for early diagnosis of various diseases.

- **Conventional Methods**: These methods may include serum or urine analysis. However, they are generally not effective for early diagnosis because the markers for most diseases appear late in the disease progression.

### Step 3: Identify the Technique Not Used for Early Diagnosis
From the analysis:
- PCR, recombinant DNA technology, and ELISA are all used for early diagnosis.
- Conventional methods are not effective for early diagnosis due to the late appearance of disease markers.

### Conclusion
The technique that is not used for early diagnosis of disease is **Conventional Methods** (Option D).

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