Get your Health question answered in 3 easy steps
A Doctor will be with you shortly
Ask a Doctor Now
186 Doctors are Online

How accurate are HIV, PCR, DNA test after 28 days with antibody?

User rating for this question
Answered by

General & Family Physician
Practicing since : 2001
Answered : 11895 Questions
How accurate are hiv pcr dna test after 28 days done with antibody
Posted Sun, 4 Aug 2013 in HIV and AIDS
Answered by Dr. Michelle Gibson James 26 minutes later
HI, thanks for using healthcare magic

There are different tests that can be used to detect HIV. The PCR and the ELISA test.
PCR DNA looks for dna evidence of the virus , in other words it looks for the virus itself.
Because it is checking for the actual virus the window period is 2 to 3 weeks.

The window period is the time it takes for a test to definitively determine whether an infection is present or not.

This means that after 4 weeks or 28 days , the PCR would be able to accurately show whether some one is infected with HIV. The result at this time would be correct and the final result.

The other test, most common screening test (because it is cheaper), the ELISA tests detects the presence of anti bodies.

Antibodies are formed in a person when they react to a particular antigen which could a bacteria, virus or fungi. In this case it is the HIV virus.
For this reason the window period of the ELISA is 3 to 6 months because it can take up to this time in some persons for the antibodies to form.

The PCR test is a antigen dna test, it does not look for the antibody but if you did the antibody test , a definitive result would be in 3 to 6 months.

I hope this helps, feel free to ask any other questions
Above answer was peer-reviewed by
Follow-up: How accurate are HIV, PCR, DNA test after 28 days with antibody? 28 minutes later
would you say i was hiv neg ?
Answered by Dr. Michelle Gibson James 10 hours later
Hi, yes if the PCR was done at day 28 then you would definitely be HIV negative.

Please feel free to ask anything else
Above answer was peer-reviewed by
Share on Facebook
Share on Twitter
Share on Google+
Question is related to
Diseases and Conditions
Lab Tests
Medical Topics

The user accepted the expert's answer

Ask an HIV AIDS Specialist

© Ebix, Inc. All Rights Reserved.
All the information, content and live chat provided on the site is intended to be for informational purposes only, and not a substitute for professional or medical advice. You should always speak with your doctor before you follow anything that you read on this website. Any health question asked on this site will be visible to the people who browse this site. Hence, the user assumes the responsibility not to divulge any personally identifiable information in the question. Use of this site is subject to our Terms & Conditions
Already Rated.
Your rating:

Ask a Doctor