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Date of last update: 10/12/2017.

Forum Name: AIDS

Question: Information regarding HIV NAT and ELISA test

 scorpionking_543 - Mon Dec 14, 2009 12:54 am

Hi Doctor,

Let me describe my case directly. I had unprotected oral sex(mouth-penile for 1 minute only), protected vaginal sex and mutual masturbation with a commercial sex worker in Bangkok 19 weeks back. After that I tested several times:

1. ECLIA test at 6 weeks - negative
2. MEIA test at 9 weeks - negative
3. ECLIA test at 14 weeks - negative
4. Rapid HIV test at 16 weeks-inconclusive (1st and 2nd determinate - positive; 1st and 2nd Double Check - negative)

The nurse told me that she will send one blood sample to Thai Red Cross for NAT test,another sample to another lab for ELISA test and it will take 2 weeks to get the result. She also asked me to repeat the ELISA test after 2 weeks each time for 6 weeks. Next day, I also did another test (MEIA) at another hospital which came back negative. Report showed that detection of HIV-1 and HIV-2(including Group O) by MEIA method is 100% sensitive. NAT and 1st ELISA test came back negative. I gave blood for the 2nd ELISA test and I am waiting for the result.

However, I started having SWOLLEN NECK LYMPH NODES after 13 weeks (as diagnosed by an ENT). I had swelling just below my left jaw. It stayed for 10 days and then went away for a week after taking antibiotics as prescribed by the doctor for sinusitis. Again, it came back and lasted for a week or so. Then I was well for 15 days until recently I started having swollen lymph nodes behind my left ear and below my left jaw. I am concerned whether these are symptoms of HIV infection, because I have heard that people have ARS symptoms within 2 to 6 weeks not after 13 weeks and the symptoms are not recurrent. I do not have any other physical condition like flu or rashes by date. Can you please tell me about my symptoms and whether they are HIV related.

Now my questions are:

1. What is the window period for HIV? Do I need to test so many times for ELSIA or are my 16 weeks NAT negative and 1st ELISA negative considered conclusive and definitive? Do I need to test further?

2. What are my chances of contracting HIV from one minute of unprotected mouth-penile oral sex and protected vaginal sex? Is mutual masturbation safe?

3. Does NAT test by b-DNA method look for both HIV-1 and HIV-2 or just HIV-1? How much reliable is a negative NAT by b-DNA method after 16 weeks?

Please give me your kind suggestions. Sorry for posting a so lengthy. I hope you can understand my current mental status. Looking forward to your reply. Thanking you in advance.

Please help me.Thank you.
 Dr.M.jagesh kamath - Wed May 12, 2010 9:00 am

User avatar Hello,Window period in most is 3 months but in extremely rare may be up to 6 months.Since you had taken proper precautions during the genital sex the oral sex part of it would be of low risk.
The ELISA tests and the rapid HIV tests are very accurate and a negative result after the window period of 3 months means a negative status and counselled accordingly.
Though these tests have higher sensitivity they have a slightly lower specificity in that false positive reactions do occur sometimes with minor other viral infections.
If you are reported negative by the rapid tests or ELISA after the window period and did not have any risk behaviour for HIV in this period you should consider youself HIV negative.
Confirmatory tests like WesternBlot are done with test showing positive ELISA as a routine.
Best wishes.

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