Which test is better for diagnosing HIV - ELISA or PCR?

Q: I am a 23 years old male. I have a few questions about HIV infection and its diagnosis. Please answer the same and clarify my doubts:

• Which test is better for diagnosing HIV - ELISA or PCR?
• What can be the maximum time for an individual to show HIV antibodies in ELISA Test?
• What can be the longest window period?
• I did ELISA test after 6 months, are there any chances of the test being false negative?

A:

1. PCR is a better test
2. The maximum time for an individual to show HIV antibodies in ELISA Test can be 12-14 weeks.
3. The longest window period can be 03-04 months.
4. No. The chance so the test being falsely negative are almost nil.