Dr. Tan and Partners is one of the few approved Anonymous HIV Testing Centres in Singapore. A detailed write up on our service is available here.

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HIV RNA / DNA PCR Test – Nucleic Acid Amplification Testing (NAAT)


a.k.a Nucleic Acid Amplification Testing (NAAT)

The HIV RNA test has revolutionized HIV screening especially for people at high risk.

The test directly measures the amount of HIV virus in a person’s blood.

This same test is also used to monitor how a person with HIV is responding to treatment. When used this way, it is called a Viral Load test.

The HIV RNA test is deemed to be 100% conclusive if done after 10 to 12 days from the date of exposure.

Click on the picture for the latest information on the HIV testing Window Period

Click on the picture for the latest information on the HIV testing Window Period

There are some theories that say this test becomes less accurate from about 3 months post exposure. This is because at 3 months post exposure, the body would have made antibodies to fight the HIV virus. Therefore, the amount of virus in the blood may drop below the detection limit of the RNA test.

Acute HIV infection is very challenging to identify because its symptoms are not specific and antibody tests often are either still negative or indeterminate. However, this is also the time when an infected person is most contagious due to a high viral load. Detection of acute HIV infection not only enables us to counsel the patient on taking active steps to reduce transmission, it also enables us to better identify potentially infected partners as the time span we need to focus on is still relatively short.

Currently the vast majority of HIV tests are conducted using antibody tests. These include rapid tests such as Oraquick™ (Rockeby) and Determine™ (Abbott) and also conventional blood ELISA tests.

The limitation of antibody tests is the window period. Antibody tests may not be able to pick up HIV infections for up to 3 months after an individual is infected. This is far from ideal because this is exactly the period that a person is most infectious with the highest viral load. Acute HIV infection contributes disproportionately to HIV transmission due to its high viral load and negative antibody tests.

NAAT tests for HIV require only 10 days post exposure to be accurate. It is the only option for detecting HIV infection before seroconversion.

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Benefits of NAAT include:

  1. Earlier identification of infected persons leading to reduced transmission risks
  2. Facilitate partner identification, counseling and testing
  3. Early diagnosis leads to early initiation of follow up and treatment leading to better prognosis

However, NAAT increases the cost and turnover time for HIV testing.

A screening program for Acute HIV Infection using pooled NAAT was successfully conducted by the New York City Department of Health and Mental Hygiene1. Specimens from all patients whose rapid HIV antibody test was negative were tested by polymerase chain reaction in pools of 512 specimens. If the pool was positive, component specimens were tested to identify which specimen(s) contained HIV RNA. The report findings confirmed that pooled NAAT can increase Acute HIV Infection diagnoses among high risk STD patients. It can also be used to identify areas or populations in which HIV infection is spreading.

The usual turnaround time is 2 weeks.

However, the Lab can conduct an expedited test for a surcharge.

If you wish to have a HIV RNA test done, please come down to our clinic.

There is no preparation like fasting necessary.

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Our Andrology and Infection Centre at Novena Medical Center is open.Call us at 63972095 now to book your appointment.Feel free to email your queries, feedback and suggestions on what other topics you want to see in the comments section below.If you have any questions, visit our free online forum on sexual health, HIV and STDs.1. CDC. MMWR, November 27, 2009/58(46);1296-1299

About Dr. Tan
Dr. Tan graduated from the National University of Singapore in 2001. His residency was in the two largest public hospitals in Singapore; Tan Tock Seng Hospital and Singapore General Hospital.

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  1. Dr,
    Yesterday i am expose to a girl with (non sexual contact) as what i do is touching her breast and nipple and withoit any sexual contact include handjob, fingering, vaginal, anal and oral as well.my clothes all the time cover and she just take out half way of her clothes whn i touching her breast. So dr is my exposure involve any risk of hiv and std?

  2. Hi, doctor!
    I am a 26 year old man from Brazil and had an unprotected sex with another man, whose HIV is unknown.
    After the risk relationship, I used PEP for 28 days.
    21 days after exposure I performed a PCR test, which was undetectable.
    31 days after exposure, I made a 4th generation test, which was negative.
    45 days after the exposure, I did a 3rd generation test, which was negative.
    Are my findings conclusive, Doctor?
    I am very anxious and depressed with all this!
    Thank you and congratulations for your work!

    • I would consider your 4th generation test conclusive, however the other 2 tests would not be considered useful in this setting. PEP would suppress viral load anyway, so it does not make sense to do that test. And the 3rd generation test is only conclusive after 3 months. However, as mentioned, your 4th generation test should be sufficient.

  3. Johnson

    Just had a DNA pcr test at day 12 following protected sex with a positive woman who was not on treatment. I checked the condom and it was intact but had sore throat and painful testicles for which the doc gave me jabs for sti.though I somehow rubbed my dick on her pant before penetration.the result was -ve. Can I move on with my life?

    • I would consider your testing essentially conclusive; however, PCR testing is still not considered as a diagnostic test for HIV, so if you are concerned I would still recommend a 4th gen HIV Ag/Ab test at 28 days or more.

    • Johnson

      Had a combo age/ab test on day 28 and it came out negative.

  4. Hello Doctors,After condom protected sex with Escort,i have done hiv 1 Pcr rna test on 18th day ,hiv 2 detection pcr on 23th day and on 25th day hiv duo test ,all came up negative .Is it convulsive?But I have symptoms ? Worried help me.

    • I would consider your testing essentially conclusive already. Clearly, this means your symptoms are not due to HIV. If you are concerned about any symptoms, best to visit a doctor for a proper consult and evaluation for alternative diagnoses.

  5. mailmael

    Im male 26, circumcision
    I have possible exposure condom left in vagina while penetrating
    I do these test after the exposure
    14 days antibody test -ve, 21 days antibody test -ve, 23 days pcr rna -ve, 46 days antibody test -ve, 56 days antibody test -ve. Is it conclusive?

    • I would consider the PCR -ve at 23 days conclusive, but officially you would be recommended to do a 4th generation antigen/antibody combo test to have conclusive results before 3 months. If more than 3 months post-exposure, then I would consider the antibody testing conclusive.

      • mailmael

        Thank you for your answer
        After that series of test
        I do 65 days post exposure cmia ab/ag test and the result is negative
        Is it conclusive?

  6. Hello doctor..
    My question is:

    My friend take cmia ab-ag test post exposure 95days.. Then after a year.. Take a pcr rna test then it show cd4 only 150…can it be bcoz of hiv?

  7. How are you doing dr. I had a posible exposure condom broke.. everything was fine till after 2 weeks I had a light pain swallowing and then and tender lympnode under my armpit . I suffer from severe anxiety and panic attacts so stared googling day and night I stared smoking very heavy witch I didn’t smoke any more so I stared to get scrachy throat itchy eyes and ears it lasted 5 days but runny nose around ten days . In the middle of this I took an early detection test HIV RNA QL TMA AT 24 days witch came back negative … after that I had pain in gums around wisdom tooth also had small painful red pimple like on my thongue wich I always had those lil bumps but this time one was pain ful it went away than it happen 2 more times different spot of the tongue and tender lympnode u see jaw since I had cold like . So at 38 days I went and tested with the HIV 1/2 AB/AG 4TH GENERATION test it came back negative at 38 days .. are my results conclusive at this time ? If my symptoms were related to hiv would those test pick the virus up. Please help out I’ve been so paranoid for this past 6 weeks thank u for the great service u guys do …

    • Dr. Julian Ng


      I would consider your 4th Generation HIV test done at 38 days as conclusive.

  8. Dr. Just a question: i had done hiv 1 rna pcr at 10days from exposure, 27days hiv 1 & 2 ag/ab together with the lady that i had protected sex. Another 4th gen test at 28days from exposure. All the undetected and nonreactive.can i move on my life?

  9. Greeting
    I would look for your help
    Like this
    I had sex with sex, and after the ejaculation of the condom I slipped and stayed in the vagina. I do not know what the HIV status of a worker is.
    This happened 96 days ago and so far I’ve been doing these tests.
    21 day pcr rna qualitatively and qvantitativno:nonreactiv
    42 days pcr rna qualitatively and qvantitatively: nonreactiv
    60 days HIV ag / ab combo test: negative
    73 days of HIV / ab combo test: negative
    77-day fast test Elfa ab: negative
    89 days of HIV ag / ab combo test: negative
    96-day fast test Elfa ab: negative
    Are my tests finally concluded?
    Of the symptoms I have only increased submandibular lymph nodes on both sides and one on the neck, and the size is about 1 cm. Are my examinations closed and can I have sex with my wife without a condom?this is my last reply.

  10. Smitmonter

    I had unprotected sex with sex worker and I took PEP within 48 hrs.

    I took rapid (ag / ab ) test on 87th and 146th days (CMIA) method )of after exposure.
    Result is non reactive.
    but I took rapid hiv (ab) test on 151rd(gen 2)of after exposure.
    result is reactive

    Again I took Hiv test on 158rd day of after exposure (HIV RNA viral load <20 cps/ml ) also non reactive.

    Again I took blood test on 197th day (ELISA combo).
    Result is non reactive.

    is it my result is confirmed. or still do I need to take any other test to conform the my status.
    doctor help me me very thank

  11. Dr tan, i wpuld like to knw the result of pcr rna at 10days (9days and 20hours) cn be good indication?
    1. I got taking pep for 1 days and discontinue would it effect the test result?
    2. Dr will the result will be difference if 9days 20 hours or 10days?

  12. Worried

    Hello Dr,
    I was taking lots of antibiotics from 8 days after exposure.And in between I have done test with tridot kit on day 13. Still I was taking medicines. After that I was admitted in hospital on day 24 of post exposure and did test with tridot kit for HIV antibodies and also done au antigen. And also taking vitamins injections. After that on day 28 of exposure I did RNA quantitative pcr test. And also did western blot on day 43 of exposure. All tests result came negative. But now on my palm of hands I have one red dot and also on left elbow I have three red dots which are not itchy. Should I go for HIV test or not ?