[Question #2625] HIV result interpretation

44 months ago
I am female. Performed oral sex without protection, on male of unknown status, last year in June and July, on four or five occasions. We had vaginal sex as well and condom was used without fail.
The test was done early last September. I am certain I waited at least 4 weeks since the last encounter but not sure about 6 weeks.

HIV test came back as: 

HIV 1/2 ab/ag test with reflexes: non-reactive 
HIV 1/2 ab ID code: not indicated 
HIV-1 RNA, TMA, Qual Code: not indicated 

I am confused by these results. 
1. Were all three tests listed performed or only the first one (I vaguely remember that the nurse drew two tubes of blood)? Does "not indicated" mean the test was not performed or no virus was found? Sorry English isn't my first language.
2. What does "with reflexes" in the ab/ag test mean? 
3. Why is the window period changed from 4 weeks to 6 weeks? Is it because antibody might be too low after antigen disappears?

I know I am of very little risk but getting answers would really ease my mind!! Thank you!
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
44 months ago
Welcome to the forum. Thanks for your confidence in our services. My first comment is to congratulate you on having safe sex during your brief relationship last year, since you apparently didn't know (and still don't know) his HIV/STD status.

This is an example of a not uncommon problem of patients seeing their own medical records, lab results, etc. All in all, that's a healthy trend, but lab results terminology are designed for professionals, i.e. patients' physicians. The answer is very simple:  "with reflexes" means that there is automatic testing in sequence, if the earlier test is positive. The first line of your results is negative. Therefore, the next test was not necessary (i.e. "not indicated") and not done. Ditto with the tests in the last line.

Those comments answer questions 1 and 2. Only the initial test was done. 

Question 3:  Until recently, the available data suggested the 4th generation tests are conclusive at 4 weeks, but a new journal article reviewing HIV test performance (not yet published) concludes that on rare occastions, it takes as long as 6 weeks to become positive. It's rare, and 4 weeks usually is conclusive -- but on this forum we now advise 6 weeks, to be on the safe side.

In any case, you were at little or no risk of HIV from the exposures last year. Probably your partner didn't have HIV, assuming he isn't bisexual, an injection drug user, or otherwise at high risk. But even if he had HIV, you had only safe sex. HIV is rarely transmitted penis to mouth:  one estimate is that the risk is 1 chance in 10,000 for each exposure. That's equivalent to performing oral on infected men once daily for 27 years before transmission might be likely. Even if your HIV test was done 4 weeks after the last exposure, in this circumstance you can consider it conclusive. However, given the latest information about the 6 week window, you could consider having another test for additional reassurance. If you do it, you definitely can expect another negative result.

I hope this information is helpful. Let me know if anything isn't clear.

44 months ago
Thank you for your response! 
I asked my partner and he said that he is "clean." Although he has never been tested and is not planning on doing so since he "always use a condom." He is not bisexual but he has had multiple partners. He ejaculated in my mouth two times, which is what I am worried about.
My main question now is how conclusive is the test at four weeks? And at five weeks? I understand that the test is completely conclusive at 6 weeks, but I honestly cannot remember whether I waited 6 weeks since the test was done last year.
I have been reading everywhere that the antibody starts appearing around 2 weeks, and declines after 4 weeks. Is this not the situation anymore?
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
43 months ago
I apologize for the inordinate time it took me to see and respond to your follow-up message. We're hoping for new forum software in the not too distant future -- which will provide more effective alerts to follow-up comments. If you have had another 4th generation test at 6+ weeks, as I recommended above, the negative result is conclusive.

Your closing statement/question mixes up antigen and antibody. Antigen starts to be detectable in the blood around 10-12 days and wanes over a few weeks. Antibody starts to appear around 2-3 weeks, is almost always present by 6 weeks, and remains for life. In any case, oral sex is very safe, with only a handful of proved cases (in 30+ years and among millions of infected persons) have been acquired by oral exposure to semen.

Threads are normally closed when there has been no activity for a month -- but the delay was my fault, so I'll keep this open a few more days in case you have any final comments or questions.