[Question #13397] 4gen test window

5 hours ago

Hello Doctor,

I know you advised that my exposures didn't have much risk

But can I ask you some doubts about the 4gen combo test just to be sure?

- Why was before conclusive at 28 days and nowadays at 42 days? I saw a doctor from Venezuela that claims as very accurate this test from day 15 because the antigens

- For example if your last extramarital affair was 24 July, then you have sex with your partner lets say on 1 August and you have a negative 4gen test done on 25 August, there is a possibility that you could transmiten her at that time?

- Can I be calm with a negative 4th generation test done at a clinic It was rapid, but it was from a vein 32 days after exposure?

There is much information on the internet which says that 28 days is too early, its scary

Obrigado

Edward W. Hook M.D.

4 hours ago

Welcome back to the Forum although I’m sorry you felt the need. You need to stay away from the internet where much of what is there is incorrect, particularly given your tendency to be hypochondriacal. You are worrying about problems that do not exist.

The assessment of when 4th generation tests are conclusive was changed years ago following descriptions of a very few cases which became positive between 4 and 6 weeks. This is very rare. Neither of us have ever seen or heard of such a case.

With a negative test on August 25, there is no way that you could have transmitted HIV on August 1.

Believe your test results. Both rapid tests and tests performed on venous blood provide equivalently accurate results.

Please don’t worry. EWH

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3 hours ago

Thanks doctor again for your time and reply

I know Quora its crazy, although it is true that there are also some well-founded specialists or researchers who give advice similar to yours.

- Regarding this With a negative test on August 25, there is no way that you could have transmitted HIV on August 1. may I know why? Even its a short explanation just to understand

- The cases which became positive between 4 and 6 weeks.were due to something special? But I guess if you who are on the field for many years never ever seen or heard about it I can be calm enough with a negative test at 32 days after a non much risk exposure right?

- Do not understand neither that I saw some literature explaining that the antigens are present mostly always around day 15 till 30 so I guess the normal thing would be for the test on these dates to be positive for antigens or antibodies.

Obrigado

Edward W. Hook M.D.

3 hours ago

Virus must be present in detectable amounts for transmission to occur. Three weeks after an exposure leading to transmission there would certainly be sufficient virus and/or antibody present to result in a positive test.

There is substantial variation in how long it takes antibody production to occur. Recommendations regarding time to positivity are based on studies of thousands of people.

What you have seen reflects what typically occurs, i.e average situations - there are typically outliers. I suggest that you accept the information provided which is based on high quality scientific research.

One follow up remaining. EWH

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2 hours ago

Thanks again doctor

To close the topic and see if I can go back to living my normal life without worry.

1 - So if I understood it correctly, if for example there was a possibility of transmitting on July 31 / August 1, then a test after 25 days (25 August) it should have been positive, right? There is no margin for an infection, for example, that could be just starting no?

2 - Dr Hook, after a negative result 32 days after a low-risk contact, there would be no need to repeat the test at 42 days? And there would also be no need to worry about HIV2, since it's rare in Europe, right?"

3 - In a healthy person, the most normal thing is that the antigens would have appeared in around 3 weeks, and a test at 28 days would be quite conclusive, right? I understand that the appearance of antibodies can vary more, but since it was a 4th generation test

Muito obrigado

Edward W. Hook M.D.

1 hours ago

Final responses

1. Correct.

2. Repeat testing beyond day 32 is a personal choice but the likelhood that you were infected and that the infection would be missed is virtually zero.

3. Correst

End of thread. EWH

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