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How accurate are 4th generation tests?

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Posted on Mon, 6 Apr 2015
Question: Hi ,
I happen to had a sexual encounter for the first time before 28 days.I used a condom but it broke .I had a 4th generation test on the 16th day after the possible exposure and the result was negative. I read that 4th generation tests a highly accurate and detects the virus after 16 - 28 days.Today is my 28th day and I want to take another 4th generation test on 3oth day.
Could you please recommend me which test has to be taken either 4th gen or PCR RNA or any other.
I am scared a lot ,
Are the test results of my previous test can be consired.If yes what are the chances that I might not be infected with HIV?
I read in many articles that 4th gen tests are almost conclusive after 16 days.
Could you please suggest me what to be done.I could not take this off my chest from the day 1 .
doctor
Answered by Dr. Praveen G (1 hour later)
Brief Answer:
4th generation tests are highly specific

Detailed Answer:
Hello
Welcome to Healthcare Magic,

I have gone through your history and understand your concern.

4th generation tests are sble to detect HIV antigen as early as 10 days of possible exposure.

As your tests are negative at 16 th day the chance of havong HIV infection will be very very less.

But as there is a window period in case of HIV virus you need to test with 4th generation tests at the end of 90 days of possible exposure.

The 4th generation tests can detect both sntigen and antibody of HIV virus. If it is negative after 90 days it is 100% confirm that you are not having HIV infection.
Thank you.
Above answer was peer-reviewed by : Dr. Vinay Bhardwaj
doctor
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Follow up: Dr. Praveen G (34 minutes later)
I had HIV I and II ELFA test in Apollo. As Iam going to take the same test on 30th day.Is it enough for concluding.What can b the Percentage chance that I am not infected.
I will take the same test after 90 days window period as per the protocol.but as per the above test.can I conclude Iam MOSTLY free from HIV.
doctor
Answered by Dr. Praveen G (1 hour later)
Brief Answer:
Day 90 test is confirmatory

Detailed Answer:
Hello
welcome back

The negative reports tells that you are not having HIV infection but it is 100% confirmed by the day 90 test.
Thank you.
Above answer was peer-reviewed by : Dr. Prasad
doctor
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Follow up: Dr. Praveen G (3 days later)
I had another hiv I and II elfa test on the 30 th day and result came non reactive.could you please xplain my chances of havin hiv even though the result is non reactive.I have attached my report.i heard these tests are pretty accurate after 28 days.xplain mynchances of being hiv free
doctor
Answered by Dr. Praveen G (19 hours later)
Brief Answer:
The chance of having HIV is very very less

Detailed Answer:
Hello

Welcome back,

I have gone through your attached lab reports.

As it has come negative after 30 days of possible exposure, the chance of having HIV infection will be very very minimal. Almost nil in that case.

Another test after 90 days will confirm 100% whether you have HIV infection or not.

Thank you.
Above answer was peer-reviewed by : Dr. Shanthi.E
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Answered by
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Dr. Praveen G

Infectious Diseases Specialist

Practicing since :2002

Answered : 2448 Questions

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How accurate are 4th generation tests?

Brief Answer: 4th generation tests are highly specific Detailed Answer: Hello Welcome to Healthcare Magic, I have gone through your history and understand your concern. 4th generation tests are sble to detect HIV antigen as early as 10 days of possible exposure. As your tests are negative at 16 th day the chance of havong HIV infection will be very very less. But as there is a window period in case of HIV virus you need to test with 4th generation tests at the end of 90 days of possible exposure. The 4th generation tests can detect both sntigen and antibody of HIV virus. If it is negative after 90 days it is 100% confirm that you are not having HIV infection. Thank you.