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 4th Generation Test Singapore

The HIV 4th Generation Test is one of the most accurate and fastest way to determine is a person has been infected with HIV or not.

The HIV 4th Generation Test is also called the Combo test or the Duo test.

It tests for both the HIV antibodies as well as the antigens in the blood. It can be done as a rapid test i.e. you can get the results in 20 minutes.

Antibodies are produced by the body when it is infected with the HIV virus. There are many different types of antibodies. The one that is produced the earliest is called the IgM antibody. This can be produced as early as 20 days post exposure. 3rd and 4th Generation HIV tests can detect the IgM antibody.

Antigens are bits of the HIV virus shell that can be found in the blood as early as 14 days post exposure. The 4th Generation test can detect the presence of this antigen.

If the test detects either the presence of HIV antibodies or antigens, it means the patient is most likely infected with HIV. This has to be confirmed with another ELISA test. We always do at least 2 tests before diagnosing a person as HIV +ve.

Officially it is conclusive at 28 days post exposure. However, from current scientific data, we know that when the test is done at 20 days post exposure, it is already as good as 100% accurate. Personally I have tested patients +ve for HIV at only 14 days post exposure with this test.

The US CDC recommends the HIV 4th Generation test for all HIV screening. This is because it is more accurate, has a shorter window period and can pick up rare cases of sero-negative infections (see below).

The HIV 4th Generation test can detect HIV infections in very rare cases of people who are infected with HIV but never produce any anti-bodies. These are called sero-negative infections and happen in about 1 in 1 million people.

At our clinics the HIV 4th Generation test costs $150 (before GST).

You can walk in our clinics at Robertson Walk, Bencoolen Street, Novena Medical Center or Scotts Road anytime during our opening hours for this test. It only requires a finger-prick of blood and 20 minutes to get results.

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If you need a HIV test visit Our Clinics anytime during our opening hours. You do not need an appointment.

 

Find out more about Anonymous HIV testing at our clinics.

Can’t wait for 3 months to find out? Find out more about Anonymous Rapid HIV Combo test at our clinics.

If you had a high risk exposure to HIV within the past 72 hours, you can take medicines to reduce your risk of actually contracting HIV. Find out more on HIV PEP Treatment.

 

Related Topics:

Anonymous HIV testing at our Clinics

HIV – Understanding the Window Period

Cost of HIV/STD tests at our Clinics

Condom Broke

Getting HIV from Oral Sex

More on HIV symptoms

How long can HIV live outside the body?


 

We are Open on Saturdays and Sundays.

Click Here for Contact Details, Address and Opening Times.

Feel free to email your queries, feedback and suggestions on what other topics you want to see in the comments section below.

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We are now Open on Weekends.

We have 5 locations conveniently located at Robertson Walk, Bencoolen Street, Novena, Scotts (Pacific Plaza) and Somerset (H&M)

Robertson Walk          6238 7810   map

Bencoolen Street        6884 4119   map

Novena                           6397 2095   map

Scotts                              6694 2348   map

Somerset                       6262 0762   map

Email: doctor@drtanandpartners.com

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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219 Comments

  1. raghav raghuvanshi

    hello doctor…
    3 days ago i went to prostitute.
    no sex took place but i n between handjob condom somewhere got off penis…
    she was finguring herself too and just touched my penis with same hand for 3-4 seconds before putting other condom…
    what shall i do now..??28 day wait is too long ….passing each day is touch…i m severely depressed

    • The risk of getting HIV from a handjob is negligible. If your exposure is less than 72 hours ago you can see a doctor about HIV PEP. If not, wait till 28 days to get tested. If you are depressed see a counselor or get your GP to refer you to a psychiatrist.

  2. floridaricky

    Hello Doctor, I did a 9 weeks and 9.5 weeks oral fluid oraquick test and the results are both negative. How likely the results are going to change? My risk exposure is to perform oral sex on a female with unknown status for 1 minute. Thanks!

  3. Hi Doctor,
    I had a protected sex and she cleaned the vaginal fluid on condom and after removing the condom with the same tissue paper she cleaned penis tip. My worry is, if she has HIV, the virus should not go inside my penis tip. Today its’s 27th day of exposure and I did 4th Gen HIV combo test and its negative.

    • I would say you are at an extremely small risk of HIV. But not because of the tissue paper incident. More because condoms are not 100% effective in preventing HIV.

  4. Hi Doctor,

    I have a question. I tested positive for VDRL, negative for RPR and negative for TPHA. What is the meaning of this? I was ill like i had nausea, lost some weight and weakness. But after 4 weeks i was okay. I also tested HIV through combo test it was negative. Hepatitis B and C both negative. What do you think could be the reason.

    • This is a question that should have been answered by the doctor who did your test for you. Please go back to see him. As a VERY SIMPLISTIC guide, 2 common reasons are 1. False positive. 2. Early Syphilis infection.

  5. worried guy

    Dear Dr Tan,

    I had a protected sex fo 5-6 sec with kissing and fingering. After this incident I took CMIA Duo lab test at 47th day, came negative. I searched on net that some people did this test more then one time and got increasing value every time. but all the values were under negative cutoff value. this made me anxious and confused.I hv some quries related to this, pl address.

    1. Is my test is Duo test and reliable?
    2. Is this test after 6 weeks is conclusive?
    3. Is variation in index value is normal under negative cutoff?
    4. what are the chances of any changes in test in the future?
    5. do you see any requirement of further testing?

    Regards

    • 1. It is impossible for me to comment on this. You should be asking the doctor who did the test for you.
      2. HIV combo test is conclusive after 28 days.
      3. Yes.
      4. Please direct this question to your doctor.
      5. Please direct this question to your doctor.

      • Worried guy

        Dear Doctor, As per the lab, it’s the ag/ab Abbott architect test. So I would like to know your view regarding the test and the conclisiveness of it along any further testing requirement.

        Regards

        • As you can see from my previous replies, we often state that it is not our place to verify the accuracy or conclusiveness of a result. We are in no position to do that. We can give you general information that the Combo test that you did should be conclusive at 28 days post exposure or later. However, as to the exact accuracy of the test done for you, you have to verify with the doctor who did it for you.

  6. Doctor, good pm. Do you consider a 28 Day 4th gen test conclusive and no need for retest if negative? Also, have you seen a negative result at 4 weeks change later on? Hoping for your response. Pls doctor. Thanks.

  7. Doctor have you seen a negative duo test at 28 days become positive later, if there are no exposures in the interim? Pls reply.

  8. Worried Man

    Doctor Tan,

    Have you seen a negative 4th gen test at 4 weeks turn into positive later on? How reliable is a 4th gen test at 28 days? Hoping for your response.

  9. Hi i tested negative for 4th gen hiv test 25 days post unprotected sex. Now 3 months has already passed since my unprotected sex. Should i still go for another hiv test again? I read from your article that 20days post exposure with a negative result is conclusive and 100% accurate.. please enlighten me. Im so worried. Are there possibilities that result will change? Hoping for your reply thank you.

    • You are mistaken. No where in our article says that a negative result after 20 days is conclusive and 100% accurate. Please do not quote wrong information. In fact, no test in the world is 100% accurate.
      What I can tell you is that your result on day 25 is a good indicator that you are HIV negative. However, you should get yourself tested again now that it is 3 months post exposure.

  10. Worried Man

    Doctor, I am planning on getting tested at 25 days for 4th Gen CMIA test. Would the result differ from that I would get if I get tested at 28 days? Hoping for your response. Thank you.

    • Practically no significant difference. But officially the test is conclusive on 28th Day. So why don’t you wait till 28th day then do the test? Because if you test at 25 days, the doctor will invariably tell you to retest. Kinda waste of money.

      • Worried Man

        Thanks doc for the response. The only thing I am concerned about is if I test at 28 days, the results will be put off for the next week since holidays are consecutive during that time period. If I get tested at the 25th day, I can get the result much sooner — meaning, less anxiety for me. But I will resched the test doc based on your advice. Thank you and have a nice day.

  11. Hello Doctor, can a 4th gen test done at 3 weeks, 31 days, 7 weeks and 9.5 weeks post the incident be considered conclusive? All the test results came out non-reactive. Should I go for a 90 day testing again?
    Thanks for your help.

    • In my opinion the 4th Gen test is conclusive at 4 weeks. Please verify this with the doctor who did the test for you.

  12. Concerned

    Mad night out 14 days ago with little recollection. Within a couple of days, small sore on gum (about a tooth width), sore throat and cough bad when in a/c, small white spot on tonsil, wheezy and coughing when running, clear/white phlegm, orange/pink small lumps on throat, mild burning sensation on gums, mild back ache. Testing advised?

  13. I had unprotected anal sex 37 days ago . I did my HIV combo test in Vietnam yesterday and it came back with negative . Should i be worried about the result at 36 days ?
    And i’m not really sure if the HIV combo test in Vietnam was the 4th generation test or not . They call it * HIV Ag/Ab Combo test * .
    i’m always looking forward to receiving your reply Doctor ! Thank you !

    • In my opinion your test is conclusive. However, you must verify this with the doctor who did the test for you.

  14. I had potential exposure to HIV 30 days ago and after 65 hrs post exposure I took the PEP (stribild) for 28 days. I didn’t miss a single dose but 2~4 hrs difference in PEP-taking time due to work for about 6 days. After 30 days from exposure, I took the 4th generation ELISA (Roche E170) test and came negative. However, I took my last PEP medication 2 hours before the test. Would that have affected my test result?

    Really help needed.

  15. “Dear doctor hope you are well and healthy . I will not take too much of your time so I will get to the point . I am 28 year old male who had vaginal sex with csw I had a condom on , it lasted for 10 seconds I pulled out of fear . The condom seemed to be intact nothing unusual but I didn’t inspect my condom too much .
    Neways after 35 days which is today I had abbot diagnostics hiv 1/2 ag abs combo model number ci4100 4the generation . And i tested negative Should I be worried now ? Is the test conclusive ? Should I be worried . Thank you for time and patience”

    • In my opinion your test is conclusive. Please verify this with the doctor who did the test for you.

      • Thank you doctor , may I ask why everyone out there say 6 to 12 weeks in a minimum requirement ?

  16. Hi doctor had Sex with a street hooker ,condom broke,felt week and some minor pains inside my penise after Sex,but it disipitated with time.61 hrs later took some PEPs experienced some side effects like vomiting & diarea however side effects silenced after 2days, then exactly 2weeks start to experience flu-like symptoms (soar troat,difficulty in breathing,fatigue,chest pains,runny nose) with that In hand(21 day after exposure) went to a doctor did a 4th generation tests came back ,am I right at dimming the possibility of PEP’s affecting the result since I’m still on my 28 day PEP treatment?also doctor I have looked all over but no article has seemed to explain the cause of the tiny movements(worm like movements) I experienced and still experience after Sex with the hooker.

  17. Alehandro

    Daer Dr Tan
    Hello from Turkey!
    ı got my test one of them was at 14.day and another one was at 21.day test was vidas hiv duo ultra 4 Gen. Doc said that its almost %100,and one lab in turkey says vidas hıv duo ultra at 14.day %99.88
    I jut wanna learn your opinion about test at 21.day is it almost certain ? I really need help and tommorow ım going to test again at 41.day it will be certain ?
    Soory for my really bad english 🙂

    • Hello from Singapore.

      I agree with both your Doctor and the Lab. Your tests are very close to 100% conclusive. However, they are only officially conclusive at 28 days or later.

      • Alihandro

        Thanks doc i got another teat at 41 days.Can i move on ? Is there any chance to my results change ? Cause my risk was high.
        Thank you Dr.Tan

        • I do not think you should come to this platform to verify the accuracy of your results. We have to make too many assumptions. You should instead ask the doctor who did the test for you.

  18. Hi Doctor Tan,

    I wanted to ask you that will the VDRL test become negative after treatment or will it remain positive for life.

    • That is a good question. As a general rule, be prepared that both the VDRL and TPHA tests will remain positive for life. For some patients the tests do become negative after an average of 7 years. However, patients who end up having a negative VDRL usually oscillate between the test being negative and being positive with a 1:1 titer. This is called serologic scarring. It is harmless and does not mean you are still infected with Syphilis.

  19. I’m made combo test at 24 days .I have two swelling lymphocytes. Glade in both side in my neck. Only

    • The combo test at 24 days is very accurate but cannot be deemed to be 100% conclusive. You should repeat it at 28 days. However, you really need not be too worried about HIV.

  20. Depressed Soul

    Hi Doctor Tan,

    I am male 26 years old. I am very depressed nowadays. I had sex with a female sex worker on July 24, 2016. Two weeks after that i started to have flu like symptoms. I also had weight loss, fatigue, white thrush and nausea. I tested for syphilis and HIV on August 25, 2016(32 days after exposure). My syphilis was positive but the HIV I/II Ag/Ab Combo on Abbott Architect was negative 0.07. I became restless. Then i again tested for HIV I/II Ag/Ab Combo on September 2, 2016(40 days after exposure) it was negative 0.15. The nausea etc have gone but the thrush is still there. I am very depressed. Please tell me if i have HIV.

    • The fact is you have had 2 tests that say you do not have HIV. Both tests in my view are conclusive. Obviously, I am in no position to verify the accuracy of your tests. The best person to do that is the doctor who did the test for you. I suggest that you go back to see him and discuss with him the accuracy of your HIV tests and the need for retesting. Please also get your Syphilis treated.

  21. Mr Depressed

    Hai Doctor..I have done several HIV test and my post exposure is on 13 June(0 Days).

    i) 8 days (20 july) – 3th Generation Antibodies Rapid Test (Non Reactive)
    ii) 31 days (13 july) – HIV-1 RNA Qualitagive NAT (Non Reactive)
    iii) 53 days (4Aug) – 4th Generation Abbott Architect HIV Ag/Ab Combo Test (Non Reactive)

    Question: a) Is my HIV test conclusive ?
    b) can i really move on with my life from this problem ?
    c) Does a re-test at 90 required based on my previous HIV test?

    -Sincerely Thanks –

    • I personally see no reason to doubt the accuracy of your tests. However, the best person to give a final answer on the accuracy of your tests and the need for retesting or otherwise should be the doctor who did the tests for you. Please see him again for that.

      • Mr Depressed

        I didn’t see any doctor regarding on my test, all the test that i have done is based on the info that i read on the CDC & Your Website.

  22. Neville Page

    How accurate is a 4th Gen Duo test done at 4 weeks and 6 weeks post completion of PEP?

  23. Hy

    I had 1 unpotected vaginal sex (i m male). with a high risk person.
    I had an ECLIA 4th gen. test at exactly day 32. Was negative. i had a night of heavy drinking 2 days before and smoked some weed. Could it affect the test?
    I m so worried. i can’t sleep, I can’t eat.

    thank you,

    • I am not aware of any scientific proof that either heavy drinking or smoking cannabis affects the accuracy of HIV tests.

  24. Anxiety Freak

    Hai Doctor…i have one question that i hope you can answer this. Is the 4th Generation HIV Combo test conclusive at the 53 day of the post exposure? do i need to do a re-test again at the 90 day? I have taken the test at the 53 of my exposures and the result is non reactive.

  25. how reliable is a duo 4th gen test at 11-12 days? is this a good indicator? I know I will have to retest. CBC was also normal.

    • In my opinion the 4th Gen test is only conclusive at 28 days. For medical advice on retesting requirements, please check with your doctor.

  26. I had unprotected vaginal sex in Thailand with someone with an unknown status and tested negative with a 4th gen duo test at 11-12 days, how reliable is this? I know I will have to repeat the test but just would like to know if this is a good indicator?
    The girl said they went and got an antibody test done yesterday and sent me the result paper which was negative.
    I have never had a fever but hot body/hot flush feeling and clear flem on my chest after a week exposure and throat seems to get worse now at day 13. Other symptoms after 1 week were pain in groin, testicles, lower stomach which I took Zithromax for and all have gone now apart from my groin, diarrahea for only 1 day at day 10. I had a cbc at 10 days which also came back normal. Do these sound like possible hiv infection symptoms? I would have thought fever would have been the first?
    I have been diagnosed with herpes simplex 2 as fyi.
    After 10 days I also tested for hep b, syphilis and chlamydia and all clear.

    • Your symptoms do not sound like typical HIV ARS. At 10 days the tests for Hep B and Syphilis are both not conclusive.

  27. José

    Dear Doctor,

    On June 11th I had protected sex with a sexworker in a redlight area of Nürnberg, first received oral and then we had vaginal sex (I was the active partner). On June 28th I had a Elisa 4th Gen Test – HIV 1/2 Ag/Ab and next day resuslts were “Not Reactive”. According to results sheet, they used the method: CMIA, Architect Abbot. My plan is to get tested again in 90 days.

    Do you think this is a reliable result despite I got tested 17 days after possible infection?

    Thank you.

    • drtan

      Yes it is very reliable. You really need not be too worried. Also, your exposure is extremely low risk. You should test again after the window period is up but you really need not be too worried.

  28. Jesse

    hi, ive taken the 4th gen hiv test at 28 days after exposure. is the test result conclusive or do i have to take another test after 3 months. also, does the 4th gen test detect all strains of hiv? thanks

  29. hi doc
    I had protected anal sex(bottom) and unprotected anal sex, I tested negative after 27 days, it was a 4th gen elisa test.
    Is this test 100%accurate and should I stop worrying? thanks.

  30. Hello Dr, I had a negative RNA at 14 days and a negative 4th gen combo at 29 days. I should feel confident in these results correct? What about the HIV 2 concern since the combo only looks for hiv1 antigens. 4 weeks 4th gen antibody negative for hiv2 good sign?

    • Yes, you should feel confident with these results. If you are still concerned, you can get a HIV antibody test done 3 months from exposure.

  31. Hi doc, I am a boy of 25 years. time ago I received oral sex from a girl of my age (she has practiced it to me) and she had the braces. I wanted to know if the situation is at risk hiv? I made two HIV tests COMBI PT at 28 and 39 days after the incident. I close here the situation? because for about three weeks I had a fever of 37-37.1 degrees and chills.

    • Risks of contracting HIV from oral sex is low, regardless of whether braces are involved. If you 2 tests were negative, I do not think you have HIV.

  32. Jesse

    Hi doctor, ive recently gotten a 4th gen test done at 14 days. Due to various different sources, im unsure whether it’s accurate or not. I’m aware that it is not conclusive but can i know how accurate it is at 14 days. Thanks

    • A negative result on day 14 is a good indicator that you have not been infected. However, you should repeat it again after day 28.

  33. hello doctor.
    1.i know p24 ag test after 17 days is not conclusive but based on your experience how much insurance will it give after 17 days of exposure?90 percent or less or more?

  34. Had unprotected virginal sex and in about a week time had rashes, white tongue, went to hospital after one month and doctor gave me some drugs and the rashes went away and he tested me for hiv and it was negative. I still have the white tongue and have been reducing weight and went and test for hiv with 4th generation at 85 days and still negative, but I’m still reducing weight, later a lot of lab test was done and doctor says i have typhoid.. Can typhoid cause wasting of body and is my hiv test conclusive?

  35. Hi doc,
    Even though i had protected sex, i fear that i am still expose to hiv virus.
    What are the chances?
    My body starts appearing rashes, but could probably be eczema
    I also had a sore at my lower lips which i assume is probably pimple?
    My exposure is around 12 days, is it too early for symptom to appear?
    If symptom do appear, a hiv test would probably shows result as positive?
    Really in help needed.
    Thanks doc

  36. please help

    Hello doc
    I had unprotected oral sex, her vaginal fluid touched my tongue.
    I did HIV 1/2 screening test (HIV Combo)) after 28 days of exposure which came Non reactive(0.09), should i consider my 28 days test conclusive. I have symptoms like joints pain, body rash, soar throath. And also let me know should I need to do other Stds test?
    Doc your reply would give great peace of mind to me.

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