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.

Other STD services: Early STD Screening, Rapid Hepatitis B Blood Test, Swab for Gonorrhea and many more... contact us to make an appointment now!

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.


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.


Click here for HIV Testing FAQ

More on HIV symptoms.

If you have any questions, visit our free online forum on sexual health, HIV and STDs.

Click here for Info on STD Symptoms in Men
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Click here to see the full range of our HIV/STD Services

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?




Need more advice?

Come down to Our Clinics for a discussion with Our Doctors, or call our clinics for more information:

1.) Robertson Walk (Anonymous HIV Clinic)  (+65 6238 7810)

2.) Bencoolen Street (+65 6884 4119)

3.) Novena Medical Centre (+65 6397 2095)

4.) Scotts Medical Centre (+65 6694 2348)

5.) Somerset – Orchard Building (+65 6262 0762)

6.) Katong – East Coast Road (+65 6635 2551)


Where to find us – here

Selected clinics are open on Saturday and Sunday.


Email: doctor@drtanandpartners.com


All Our Doctors are Fully Certified and Trained to conduct specialised HIV Testing.


For lady patients who prefer female doctors, we have professional certified female Doctors to attend to your medical needs.

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.

Find the profiles of our panel of doctors.


  1. I(top) had protected anals and unprotected orals with 2 guys on 14th dec and 24th dec. On 31 st dec.. i received unprotected orals from a guy.. i suspect he is hiv positive.

    Since 9th jan i have had number odf helth issues.. like cough and sore throat and mild fever not above 98 f.. coughing stopped since 2 days however sore throat still on and now its painful.
    Since 13th jan to 18th jan i had very bad cramps in whole body. Doc asked me to go for medicak test.. in reports.. vitamin b12 and d deficiency. Liver and spleen enlargemnt and kidney stones. Medication on.. stomach pain stopped. On 6th feb, i had swollen lymph on neck.. so i got scared and took viral load test.. which shown 1109 copies/ml.. hence on 9th feb visited hiv specialist.. who said report is wrong and took 4th generation elisa test and hepatitis test.. which was negative(non reactive).. though he suggested retest is not required am very scared.. since 10th feb i got granular pimples on forhead and i have started headache.. since today morning am feeling short of breath.. head ache and feels like vomiteeing and very mild fever.. i can feel my body is hot.

    Please suggest.

  2. Hello doc,
    My risk was french kissing. Although it is a low risk exposure I can’t stop panicking. I had done a HIV duo test (CLIA) at 65 days which was negative. But I’m still under severe stress. Can I consider my results as conclusive and move on? Please help!

  3. After a exposure of risk with a unknow hiv status person, I made 3 test with 41, 61 and 92 days, ali negative,all test 4th generation.
    Now with almost 120 days my limple gland is a little swollen (only 1 gland right side of neck)

    1 are my test conclusive?
    2 sould I be worry?

  4. Hi doctor,
    I will begging you sir.
    This is my last question pls replay me sir.
    First of all I would like to thank you for helping so many people with your knowledge and experience.
    Is there a different for 4th generation rapid test kit and 4th generation lab test? Are the windowperiod the same ?
    1).Which company 4th generation rapid card use your hosptal ( alere combo (or) cmia combo )pls tell me sir.
    2).I will do alere combo test ofter 1.4 years result is negative. My result is conclusive iam ok but i am worry about hiv dealy seroconversion iam be come positive .
    Pls clarify me sir 1 & 2 points

  5. Hello dr. Tan ,
    Sara from Iran.
    I took a test 18 weeks after unprotected anal encounter with a male with unknown hiv status. The method used was ECLIA Combi pt 4th Generation done by Roche. The result was negative. And I haven’t had any encounters , either protected or unprotected during this time. Is my test conclusive ?
    Thank you in advance!

  6. Hi doctor,
    First of all I would like to thank you for helping so many people with your knowledge and experience.
    Is there a different for 4th generation rapid test kit and 4th generation lab test? Are the windowperiod the same ?
    1).Which company 4th generation rapid card use your hosptal ( alere combo (or) cmia combo )pls tell me sir.
    2).I will do alere combo test ofter 1.4 years result is negative. My result is conclusive iam ok but i am worry about hiv dealy seroconversion iam be come positive .
    Pls clarify me sir 1 & 2 points

  7. dear doctor what is the science behind 4th generation negative at 60 days .??why not 90 days??

  8. Dear doctor in barber shop while he trimming I had small cut hardly drop of blood came out. If same trimmer used to other person is der any chances to get hiv?
    Everyone saying no risk.

    And also I have taken hiv ag/ab at 25 days
    Its negative
    Is dat test is 4th generation test?
    Do i need one more test?

    • I would consider your risk close to zero.

      • Dear doctor, I had protected sex with a woman on 5 dec 2017 and took a test Hiv 1-2 Anti-Body and p24 antigen (enhanced chemiluminesence method) at close 8 weeks and 4 days.
        It was a non reactive.
        Is this a 4th gen test??
        Are the results definitive?
        Please suggest if further testing is required

      • I have done hiv ag/ab combo test 34th day its negative.do i need further test?

  9. Hello doctor,i had a protected (suspected that condom was torn at the tip) vaginal intercourse with a CSW. I tested negative at 7.5 weeks by a CMIA hiv combo test in sweden. Can consider the result as conclusive and move on to my life?..many thanks in advance doc. Hoping for your response.

    • I would consider your test conclusive.

      • Thank you doc.i have 1 last question though.i have read about a second diagnostic window period on 4th generation combo tests in which both antigens and antibodies are too low during the transistion from antigen to antibodies making the result negative. Is this true?if it is,how common is this?

  10. Doctor,

    I tested negative after 30 days with a 4th gen rapid test, the nurse took a finger prick sample. The event was unprotected sex with a woman I dont know her status. Should I get to be retested or my result is conclusive? In addition to my question, What is the difference between 4th gen rapid test and 4th gen lab test? Both can test an accute hiv infecction?

  11. Sir, i have unprotected vaginal intrecourse after exactly 28 days i taken 4th generation elisa test whivh value is 0.16 cut off value is 0.2 is mentioned non reactive. These results are conckusive? Plz advice me sir

  12. Hello Doctor ,
    Please help me doctor.

    Massage girl while giving massage to my body she massaged my anus also Inserted her finger in my anus for 15secs which is about 1cm went inside of my anus. Due to fear I told her
    to get her hands from there.

    I dont know wheather she has any hurt in her Finger or any cuts. I asked het she told her hand is Clean.

    I forget to check her hand.

    Is there any risk for Hiv suppose in case if there is blood in her finger while inserting her finger in the anus ?

    Not able to sleep doctor.
    Pls help.

  13. I am a male. I went to massage service. There is no sex or no oral sex
    Only hand job.
    But during the the course of massage, the massgae lady fingered my anus for 15 secs probably 1cm of her finger went inside my anus.

    Is there any chance for HIV if the girl massaged my anus with a blood in her finger ?

    Thanks doctor.

  14. Hi Doctor

    I had a rapid 4th Gen HIV test 6 weeks after engaging in oral sex with a guy.

    Is the results conclusive?

    Thank you in advance for your answer.

  15. Hi doctor, I did frottage with 2 guys at different dates, then discovered a tiny cut/abrasion below my coccyx, it bleeds very very little when rubbing with toilet paper, I can’t remember if the guys had any precum, they didn’t ejaculate… I had a 4th generation CMIA test, at 41 days from one guy and 24 days from the other one, my questions:

    1. is that considered high risk?
    2. how reliable is my test?

    Thanks doctor, I’m really worried about getting HIV

  16. Hi Doctor,
    I had unprotected oral sex , tested negative at 25 days with the 4th generation rapid test . what r my chances of test +?

    • Your chances of testing positive are essentially zero.

      • Hi doctor, I had protected sex only once with a woman but became paranoid about HIV as I didn’t check the comdom for breakage or tear.
        Tested with duo combo ag/ab test at 2,4 and 6 weeks.
        Should I stop testing and move on? Are my results conclusive, regardless of condom breaking or not?

  17. dear doctor

    why indian doctor is not agree on DUO test negative is not comsider conclusive at at 9 week?? i told them famouse doctor from singapur Dr. Tan is always saying DUO test 100% comclusive at 9 weeks and no need to further testing.. kindly help.me with logic about DUO test behind of this…is it 100 % conclusive at 9 weeks?????

    1. when antibody is started in blood then they attack on p24 antigin????

    its means DUO test at any time if anyibody is not in blood then p24 antigin always available nefore antibody started??

    i want to give answer to my indian doctor becouse i think he dont have enough knowledge ..so please give me answer in detail.. thanks

  18. Hi Doc

    Would a cycle of testosterone enanthate (anabolic steroids)have any effect on an hiv combo test? Ive tested neg at 16 weeks on a duo test!! Is this considered conclusive??

    • No, it would not affect your result. It is considered conclusive.

      • Hi Doctor,

        In your opinion, are below test conclusive for HIV

        HIV AB/AG (CMIA) – 38day – Non reactive
        HIV Rapid Test AHP (Finger prick) – 83day – Negative

        Do you agree test result overrule symtomp?

    • I was on a 12 week cycle and ended it 2 weeks prior to the incident!! So it wouldnt have had any effect on the test at 16 weeks?

  19. Is 60 days hiv duo combo is conclusive???

  20. Dr. Murli

    Dear Dr.Tan

    i am HIV specialist from Sri Lanka. i have some questions for you..

    1. how much you sure about 4th generation DUO combo test is comclusive at 28 days and why?

    2. In what Basis you are telling poor people no need to test after 28 days negative??

    3. if any pateint will take time to make antibody after p24 disappear ..then who will resposible.

    4. for example.. if someone test at 9 week and p24 not available and antiboday take time then thier is chances of false negative?? EXPLIN ME THIS POINT……

    5. so what do u think 28 days is very risky to advise people to move on…i am right??

    answer me here only please so people will make sure thier daughts..

    if p24 disappear then tested is worth if someone not make antibody??

    please focus on poimt 4

    thanks in.advance

    • You are clearly not an HIV specialist as you purport to be if you are asking these questions. The p24 antigen levels will only reduce in response to rising antibody titres. There is no period (especially at 9 weeks) where antigen will be negative and antibody has not reached a detectable level.

      • Dr. Murli

        j said i an working with very famouse hiv specialist..i am juniour..

        is someone tested at 9 week wwith 4th generation what you will not suggest him to test if symptomps also thier??


        • Your story makes no sense. If you work with a “famous HIV specialist” wouldn’t you rather speak to them in person with your questions instead of posting comments on a website for a clinic in Singapore? Stop wasting our time please.

  21. dood morning doctor.

    i had big mistake. unprotected vagina sex for short time..after 62 days i had 4th grneration CMIA blood test from lab and its negative. please doctor tell me if it is conclusive

    1. any chances if falls negative at 62 days

    2. can i repeat test at 12 weeks??

    thanks and apriciate to your good job for helping people

    • The 4th gen test is conclusive at 28 days or more. You can repeat your test if you wish but I do not believe it is necessary.

  22. Anthony

    hello doctor

    after unprotected vagina i did 4th generation test at 7.5 week in your lab. thanks god is negative. how many chances of false negative?? and do i need any testing further. thanks please reply me in detail.

  23. 4th generation duo test at 9th week… Any chance of false negative???

    • I am a male 25 yrs old received unprotected oral sex and protected vaginal sex. I had headache,sore throat and white layer on my tongue at 9th week. I tested negative at 8th,9th,10th,11th(77days)week. It was a antibody rapid test only. Is this conclusive??? Is there any chance it will change after 84 days??? Am I safe???

    • Not in my opinion.

  24. I am a male 25 yrs old received unprotected oral sex and protected vaginal sex. At 9th week I got headache and sore throat and white layer on my tongue. Tested negative at 8th,9th,10th,11th week. It was a antibody rapid test only. White tongue is still in my mouth. Is my test is conclusive??? Is there any chance my status will change at 12th week.

  25. hii doctor

    after unprotected vagina sex for 10 seconds i did 4th generation duo CMIA test at 8 weeks negative. but i have red hand palm from last two months. and many pimples on back..is my result is 100% correct or i need one more test at 12 weeks?? is thier anybchance of false negative ag 8 weeks… pls reply me in detail

    thanks for helping

  26. hii doctor

    i tested 4th generation duo combo at 9 week negative..can i assume this is my final test. vagina unprotecyed sex

  27. i had rapid hiv combo test after 77 days from the exposure it was unprotected viginal sex but i’m still scared can i move on ? anyway and do rapid hiv combos test results come after 2 hours ?cuz the doctor said i go back to her after 2 hours and the blood they took it from my vein

  28. Hi doctor,

    Is there a different for 4th generation rapid test kit and 4th generation lab test? Are the window period the same?

  29. Ravi shankar

    Is there any pcr test for HIV2 early detection. Most of the health clinic i see offer only HIV 1 PCR test.

  30. Would it be conclusive at 33th day after exposure for a elisa 4 th gen test?

  31. Dear Dr an anwer would be highly appreciated.

    Would a negative HIV Duo test (Cobas by Roche) at 35 days and 53 days rule out infection even for HIV type 2?

    Many thanks,

  32. James ong

    How accurate is elisa test ab/ag at 26 days post exposure which is two days short of the recommended 28 days. Is it conclusive as well?

  33. Hi, Would a negative HIV at 35 days and 53 days rule out infection even for HIV type 2?

  34. Hello Dr I have a ? I tested negative with the hiv duo test post 20 days after exposure the exposure was the 10th of November and I tested the 30th should i re test or how conclusive is my result

  35. First thank u for responding and respecting tha questions

    I had 4th generation hiv test after 30 days of exposure and it was negative

    How acuate is the result ?

    Thanks a lot again

  36. dear Dr,

    1 month before a women masterbating me and it’s vagina fluid in his hand and contact my top side of penis and we involved deep French kissing and to I fingered it’s overy and finally she rub my penis top with his hand it full of vaginal fluid.
    After this I took HIV combo test and Elisa test exactly 32 days after this two come back negative and non reactive with index value of 0.240.
    My question is

    1.From above exposure any chance for infection
    2. HIV combo and ELSIA test after 32days from exposure later test on future it has any chance to turn positive.
    3. I read some website they are saying HIV test is conclusive after 3 month only.why?
    Please give your replay

  37. Hi doc,
    I tested p24 combo in 68days after protected vaginal and unprotected oral sex the result is negative the question is :

    I have G6pd do u think it will affect the HIV test result and i need to retest after 6months?

    Or 68 is fully conclusive?

    Please advice and help

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