I did an hiv test with negative result , while i was fasting for the test I didn’t eat and drink anything before the test by like 8-12 hours.

1- So is it okay and it doesn’t affect the test result ? And there is no affect on the appearance  like antibodies on the body-system or the blood because of being fasting before the test between 8-12 hours?

2- i did HIV 1,2 ag/ab test. How can i know if that is a 4th generation test or it’s 3rd generation  ? 

The test title didn’t mention if it was 4th or 3rd it was only saying hiv 1,2 ag/ab 

Second question first:  For several years, HIV and ID experts have gotten away from the "generation" terminology to describe HIV tests, and finally that advice is taking hold. The correct terminology is antigen-antibody (AgAb) -- in other words, those tests are "4th generation" by definition. The "1,2" terminology is redundant:  it indicates they test for both virus types (HIV1 and HIV) -- but all AgAb tests do that, so showing the numbers is irrelevant. (The formerly named 3rd generation tests detect HIV antibody only. They are just as accurate as the AgAb tests, except they require 8 weeks to conclusive negative results, versus 6 weeks for the AgAb tests.)

There is absolutely no effect of fasting, or any other aspect of fluid or food intake, on the reliability or timing of the results of any HIV test. In fact, nothing has any effect on the modern AgAb or antibody tests:  no illnesses, no medications, no medical conditions. They area among the most robust, reliable diagnostic tests ever developed, for any medical condition.

So assuming your test was done at least 4 weeks -- and ideally 6 weeks -- after your last possible exposure to HIV, you can be completely confident in the negative result.

I hope these comments are helpful. Let me know if anything isn't clear.

HHH, MD

1- To conclude, so 3rd gen test will only detect antibodies ? It will be hiv 1,2 ab ? 

Only the 4th gen will have both ab/ag ? 

2- I did the hiv 1,2 ag/ab test by 12 weeks  , i did also hiv pcr Gene-Expert test after by week , but for  the pcr test by 1 hour before the test  i did drink water and cold milk ? Still drinking milk before the pcr test have no affect on the test ? And it’s conclusive?

3- for the hiv 1,2 ag/ab test that i had even if i was fasting for 12 hours without eating food and drinking water , that can’t affect the blood on the body or reduce some antibodies ? Because of the lack of food during fasting time ? 

Thank you Doctor that was all from my side that i needed to understand 

All the best

2,3) It sounds like you were over tested, with more tests and later tests than necessary. Food or fluid intake has no effect on any HIV test, including PCR. I'm not sure why these thoughts even come to mind?? If you think about it, if you ran a billion dollar company making HIV tests, would you design and market a test that would be unreliable based on what someone happened to have eaten? Or for people who test early in the day, before eating anything? Of course not.

Thanks for the thanks. I'm glad to have helped.

Last question sir kindly 

So any test with the name hiv ag/ab it means it’s 4th generation test for sure it can’t be 3rd generation  ?

Is it preferred to have the hiv test with fasting or without  ? What will be your advice for that to fast before it or not 

"Is it preferred to have the hiv test with fasting or without  ? What will be your advice for that to fast before it or not?" It makes no difference, which I have said three times now. Why is that so hard to understand and accept?

That completes the two follow-up exchanges included with each question and so ends this thread. I hope the discussion has been helpful. Best wishes and stay safe.