HIV AG/AB Duo Combo 4Th Generation

[jj0816]

I had taken a HIV AG/AB duo combo 4th generation test 7 weeks 4 days after possible exposure.  I understand it is a 100% definitive after 28 days?  The result was non-reactive.

1. Can you wait too long to take this test?  I did not know if the there was period were the antigen would be gone and the antibody would be too weak to show on the test.

2. Should have I taken a different test?

3.  I was taking an antibiotic (doxy) a week after the exposure for about 10 days.  Do antibiotics or any other medication like cholestrol medicine could cause a false negative?  

4.  Do you think 7-8 weeks after possible exposure, the non-reactive results from the HIV AG/AB duo combo test 4th generation would be 100% definitive?

Thanks.

[Edward W Hook, MD]

No!  EWH

[jj0816]

I meant posts instead of "poss".

[jj0816]

One last question.  After reading all my poss, do I need to take another test at 6 months?  I am sorry to keep asking, but I keep reading different posts that say conflicting information.  I just want to confirm I have done everything I should.  

[Edward W Hook, MD]

Final answer.  There is a tiny chance of something like this happening, just as there is a chance that your will be crushed by a glacier while reading this.  It is just not something that is realistic for you to worry about.

This will complete this thread. EWH

[jj0816]

Doctor

I am just trying into clarification if I get in this situation again.  If the "4th generation" test does not check for HIV 2 antigen, is 28 days enough time?  What if the antibody has not shown up yet?  

[Edward W Hook, MD]

Not for antigen but antibody would be detected.  Believe your results.  You have had more than enough testing for HIV-1 and -2 - believe your 15 week tests.  You do not need more testing and I will not repeat this again.  Further repetitive questions will be deleted without comment.  EWH

[jj0816]

I read on this site that the "4th generation" does not check for HIV 2 antigen. I did not know if 7+ weeks (date of my 4th generation test) that possibly the HIV 2 antibody might not be present.  I know at 28 days that the "4th Generation" was definitive for HIV 1, but I did not know if it was definitve for HIV 2.

I have taken two test.
1. HIV AG/AB duo combo 4th generation test 7 weeks 4 days.
2. HIV 1 and 2 Antibody test at 15+ weeks.

Please confirm that I do not need any addtional testing for HIV 1 and 2.

Does the HIV AG/AB duo combo 4th generation test at 28 days cover HIV 2?

Thank  you.

[Edward W Hook, MD]

You really do not need any further testing.  The 4th generation tests, like the 3rd generation tests, would detect HIV-2, if present.  EWH

[jj0816]

Dr Hook.

I decided to have HIV antibody test for HIV 1 and HIV 2 at 15+ weeks past exposure.  I do not know much about HIV 2.  I am in the USA.  The result was non-reactive.   I was not sure if the "4th Generation" Test I took covers HIV 2. I have not had any risky exposures since the orginal exposure.  I realize I am being overly cautious.  Does the "4th Generation" cover HIV 2?  Do I need any addtional tests or has enough time passed?

[Edward W Hook, MD]

Yes.  EWH

[jj0816]

Doctor

I realize this might be anxiety, but I have a sore throat.  Small white spots on the back of my throat.  Is your advice still the same to believe the test is accurate?

Thanks.

[Edward W Hook, MD]

Believe your test result  EWH

[jj0816]

I have broken out with a skin rash around my neck and shoulders.   Should I have any concerns, or just rely on my previous test?

[Edward W Hook, MD]

No.  EWH

[jj0816]

One last question.  Are there any concerns of false negative results.  

[Edward W Hook, MD]

Welcome to our Forum.  I'll be pleased to address your questions.  The newer, combination tests which test for both HIV p24 antigen and HIV antibody represent a step forward in diagnostic testing because they provide an accurate test earlier, at 28 days following exposure, than tests which test only for antibodies to HIV.  The reason for this is because early in infection, before antibodies are fully formed, there are very high levels of virus circulate in the blood.  The p24 antigen test detects the virus and, because of the high levels of virus present in in the first few weeks of infection is a reliable test at that time.  Later, as the infection is more established, the amount of virus circulating in the blood also decline and as a result the p24 antigen tests may not detect all infections.  The reduction of virus in the blood as the infection becomes established is due in part to antibodies which then will be present from then on, throughout the course of infection.  Thus while the combination tests shorted the time to diagnosis by adding the antigen test, they do not miss more long standing, established infections.  Your 7+ week testing is reliable  and should be believed.

As for your specific questions:
1. Can you wait too long to take this test?  I did not know if the there was period were the antigen would be gone and the antibody would be too weak to show on the test.

See above.  these tests are completely reliable from 4 weeks and beyond.  You cannot wait too long for the test to be accurate.

2. Should have I taken a different test?
No, this was a fine test.

3.  I was taking an antibiotic (doxy) a week after the exposure for about 10 days.  Do antibiotics or any other medication like cholestrol medicine could cause a false negative?  
No. medications do not reduce the accuracy of the test.

4.  Do you think 7-8 weeks after possible exposure, the non-reactive results from the HIV AG/AB duo combo test 4th generation would be 100% definitive?
Yes.

I hope these comments are helpful to you. EWH