Which technique is now routinely used to detect HIV in suspected AIDS patients ?

Answer

**Step-by-Step Solution:**

1. **Understanding HIV and AIDS**:
- HIV stands for Human Immunodeficiency Virus, which is the virus that causes AIDS (Acquired Immunodeficiency Syndrome). It is important to recognize that HIV is an RNA virus.

2. **Challenges in Detection**:
- In suspected AIDS patients, the viral load (the amount of virus present in the blood) can be very low. This low level can lead to false negative results, where the test fails to detect the virus even though it is present.

3. **Introduction of PCR**:
- To overcome the challenge of low viral load, a technique called Polymerase Chain Reaction (PCR) is used. PCR is a powerful method that allows for the amplification of specific DNA sequences.

4. **How PCR Works**:
- PCR involves three main steps:
- **Denaturation**: The double-stranded DNA is heated to separate it into two single strands.
- **Annealing**: Short DNA sequences called primers attach to the single-stranded DNA.
- **Extension**: DNA polymerase synthesizes new DNA strands by adding nucleotides to the primers.
- These steps are repeated multiple times (usually 25-35 cycles), resulting in the exponential amplification of the target DNA.

5. **Conclusion**:
- Due to its ability to amplify even small amounts of viral RNA, PCR has become the routine technique for detecting HIV in suspected AIDS patients.

**Final Answer**: The technique now routinely used to detect HIV in suspected AIDS patients is **Polymerase Chain Reaction (PCR)**.

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