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.


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?


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.


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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  1. Hi, sir
    M from india. I had protected sex. After 28 days I did hiv screening test (hiv1/2. Antibody test 4th generation eia/elisa test) . It came -ve. Till 2 month I had no health problems. After 65 days of sex I am having slight viral fewer and small thoat pain.shall I retest for hiv??

    • Also I read on net that retest after 3 month is necessary. Right now here many people are suffering from viral fewer. I am bit tense . Kindly guide me.

    • In my opinion, the test is largely conclusive after 28 days.

  2. Hello Doctor, I have protected sex with a sex worker in December 2015.

    In January 2016, I did a 4th generation ag/ab test and vdrl with gribbles pathology and non reactive.

    In February until April 2016, I took four similar tests and its negative and has no fever.

    A year later in April and May 2017, I took herpes test and hiv ag/ab test in different clinic and results negative.

    I suddenly feels and experience warm and hot body inside but no fever in Jun 2017.

    Is my results conclusive?

    Thank you for your feedback Doctor.

  3. Worried

    Hi Doc,

    I did a rapid combo test in your clinic today (27 days after exposure) and have got a negative result. Should i go for a 2nd test after 90 days or this test result is as good as 100% conclusive? Thanks.

    • The test is as good as conclusive. But we cannot say officially 100% unless you have completed the 4th gen test at 28 days or more, or the 3rd gen test at 3 months or more.

  4. Last encounter was feb 15 2017

    HIV tests:

    15 May 2017: using abbott architect i2000sr ag/ab combo = repeatedly reactive

    Then it was sent to national reference laboratory.. there they did 2 assays for first stage of confirmatory algorithm..

    ELFA Test with VIDAS HIV DUO ULTRA = Nonreactive

    CIA test with SYMEX HISCL AG/AB = Nonreactive

    Thus they did not proceed to the 2nd stage and reported it as final = NEGATIVE

    Is this accurate? What might be the cause that it was reactive with the abbott architect? Which is a better 4th gen. Kit? Thank you!

    • Last encounter was feb 15 2017

      HIV tests:

      15 May 2017: using abbott architect i2000sr ag/ab combo = repeatedly reactive

      Then it was sent to national reference laboratory.. there they did 2 assays for first stage of confirmatory algorithm..

      ELFA Test with VIDAS HIV DUO ULTRA = Nonreactive

      CIA test with SYMEX HISCL AG/AB = Nonreactive

      Thus they did not proceed to the 2nd stage and reported it as final = NEGATIVE

      Is this accurate? What might be the cause that it was reactive with the abbott architect? Which is a better 4th gen. Kit? Thank you!

      • The reactive result seems to be a false positive due to some similar antibodies in your blood which have been picked up by the Abott assay. Please speak to your labs/doctors for information on the accuracy of the tests they use and local guidelines. We are unable to comment further on those issues.

    • The reactive result seems to be a false positive due to some similar antibodies in your blood which have been picked up by the Abott assay. Please speak to your labs/doctors for information on the accuracy of the tests they use and local guidelines. We are unable to comment further on those issues.

  5. Hello Dr
    I had a sexual relationship with a girl I just met ( insertive vaginal for around 2 mins and oral for around 1 min ).
    After 25 days I took a 4th generation test, non reactive.
    The girl, 26 years old told me she has neved had an std and not having any at that moment definitely.
    Still I’m very worried of having been infected.
    After 2 weeks I had diarrhea for 2 days ( ony one deposition at the time ), and a lip herpes ( I went to the beach and got sunburnt, so that might be the reason of the herpes, hopefully! ).
    It’s 25 days too son for a 4th generation test??
    Thank you

    • We are unable to comment on symptoms over the internet. Your test at 25 days is very indicative, but we will not state it is 100% conclusive until 28 days or more. Please consult a doctor in person for proper evaluation of your symptoms.

  6. Dorcy

    Hi Dr, is there any posibblities 8 week ag/ab test using Cmia will turn positive when re test at 12 week ?

    I have this symptom of body pain and joint and feverish feeling and throat feeling uncomfortable after 7-8weeks but my test on 8 weeks are non reactive ag/ab(CMIA). Does hiv symptom occur this late?

    Thanks in advanced

    • The combo test should be conclusive at 8 weeks, so I would say it is extremely unlikely you have HIV and your symptoms are probably from another illness. Please see your doctor if you are concerned.

  7. Hi Doctor ,
    I have test below test at 31 days. Does it conslusive?

    Now is 54 days, do i need to re-test?

    Does below test are gen 4?

    TEST 1) Bacterial contamination in platelet concentrates Antibodies to Human Immunodeficiency Virus Type 1 and 2 (Anti-HIV -1 & 2), Hepatitis B Surface Antigen (HBsAg) and Hepatitis C Virus

    TEST 2) Nucleic Acid Amplification Testing (NAT)

    TEST 3) Antibodies to Treponema Pallidum for Syphilis

    • Your HIV tests are conclusive and do not require repeat testing. Syphilis, Hepatitis B & C may take a longer time to become detectable in the blood (sometimes up to 3 months).

      • Thanks Doctor,

        May i know above which test are conclusive at 31 days?
        Because my doctor never say the test are belongs to which hiv gen test tools.

        Its write hiv 1 &2 mean gen 1 and gen 2 test kit?

        Sorry because I only know gen 4 are conclusive at 28 days.

        Hope you can teach me


  8. Sorry i forgot to mention that i do have bleeding gums so gargling it with the blood possibly in the water, should i get myself tested?

    • No reported cases of transmission like this. However, if you are concerned, it is simple to get a rapid test at our clinics.

  9. Hi. A few questions.
    1. If i had a small cut on my finger and brushed against someone who has a wound, whats the risk of transmission?
    2. If i had a small cut on finger and accidentally touched a used pad in the bin, whats the risk of transmission?
    3. If i used my finger to clean a spot of blood on the sink and then used the hand to gargle my mouth, what is the risk of transmission?

    Should i be worried?

  10. Hello Dr. Tan,

    I took the bioline 4th generation after 51 days of possible exposure. Results came back negative. Should I still be concerned about being infected with HIV?

  11. Hi Dr, is 8 week after exposure Hiv Ag/Ab Screening (CMIA) non reactive accurate? do i need further test on 12week?

  12. JuanUS

    Hi Dr.

    I had a low risk exposure but the problem that I found a cut on my lip so I assumed that I got an HIV since I have HIV symptoms. I went to a clininc in US and tested for all STDs at day 41 (4th generation Combo not rapid) from the exposure and all got all negative and non-reactive except HVS1. I had a doubt about the result so I tested again at day 46 in a different test lab for HIV using 4th generation ab/ag combo not rapid and got a non-reactive result. I noticed that most of the websites recommend 12-week re-test for conclusive. I am so worried, I thought that 6-week is exclusive for 4th generation. I appreciate your reply, Thanks!

  13. Hello,

    I keep reading misleading information about when to test. My exposure date was 04.15.2017, I took a HIV AG-AB 4th generation test at 41 days (05.26.2017) right before the 6 weeks. It came back negative and after reading information on different sites, it’s giving me anxiety. Are 6 weeks conclusive, or is it conclusive at 3 or 6 months? Thank You!

    • It is our opinion that 4th gen combo tests are conclusive by 4 weeks (or 6 in your case). You would only need to re-test at 3 months if you are using antibody only testing (3rd gen).

  14. Dopel

    hi Dr.

    came in your clinic tested negative 60 days post exposure and did another SD Bioline Ag/Ab Combo Test Method ICT in ASEAN country 73days post exposure.

    Do i need to repeat the test since other health agency recommend 12 week post exposure or is it good as conclusive

  15. Shobhini

    I am extremely extremely confused and more more stressed out due to difference of perspective put here. In this article DR.Tan suggests 4th generation P24 antigen plus hiv 1 2 antibody detection test can assess the rare amount of sero-negative of thsoe antigents who do not produce anti bodies. In another article too while discussing about sero-negative case, Dr. Tan also wrote that a COMBINATION TEST WHICH DETECTS P24 ANTIGEN will be good. I did a 4th generation p24 combined hiv 1 and 2 anti-body test using the very accurate CMIA method of 4th generation which is also known as the combo or duo test and very accurate. I was exposed to possible exposures in the year of 2010 after 7 years i got tested for the above mentioned 4th generation p24 antigen test along with anti bodies (combo) test. Everything came NEGATIVE but i dont understand when a man asked to DR. Tan about his two 4th generation tests and whether this would help in detecting p24 antigen, Dr. Tan outright said NO. It’s so so so confusing now. In this article Dr. Tan stipulatively mentions about the advantage of 4th generation combo test in detecting p24 which made me so soooo relieved but when i read the other artucle and the comments posted by the users, Dr. Tan is saying no it cannot detect p24 antigen sensitively but other doctors claim 4th generation is advanced and can develop high antigens fast. I am so so confused and so stressed out after reading the article of Dr. Tan. I was otherwise happy after i got a negative test after 6 years of exposure but after reading this i feel my p24 4th generation is not worth it :(. Feeling like crying. May be i did a mistake to understand what did Dr. Tan try to say. It would be really obliging helpful on ur part to help me clear the CONFUSION that is stressing me out. Please i am literaly feeling helpless. Now i feel should i get tested for RNA Viral load but now i hv no money as i am out. I was so happy at my 4th generation test accuracy. Please Dr. Tan help me clear my confusion by stating what did u actually mean to say to that man that 4th generation combo is not sensitive but in this article u specified about how 4th generation accurately detects rare form of cases which are sero-negative. Now please help me please. For your information, 4 dayss ago i did a 4TH GENERATION P24 ANTIGEN COMBINED HIV 1 AND 2 ANTIBODY TEST AFTER 6 YEARS OF UNPROTECTED SEXUAL EXPOSURE. PLEASE HELP ME I AM FEELING TOO TOO TENSED. Regards and thanks in advance.

    • It can be a bit confusing, but essentially at 6 years HIV antibodies would be in full force so your negative test is conclusive. Stop worrying – you do not have HIV.

  16. Worried 1

    Dear doctor . I did oral sex on a girl , at 21 days I was tested with a Alere determine blood prick ab/ag. Past 6 weeks I went to my doctor and did a complete STD panel including hiv 5th generation test negative. I also have tested my self with oraquick at 4,5,6,,11,12,13 weeks all negative .
    Should I Stop worrying ?

  17. Peter

    Hi Dr,

    Recently I got a massage from a Low class massage parlour. I observed that the lady there, poured some massage oil on my pennis with the head of the bottle touching my pennies. I suspect this is how she do for other customers as well. Am I at risk of catching hiv , syphillis , warts, herpes?

    Pls note there was no penetration sex. Only masturbation.


    • Hi,
      I do not believe you will get any STDs from the bottle, but there can be theoretical transmission of warts/herpes from skin-to-skin contact, i.e. the masturbation itself. Probably very low risk.

  18. Mranxiety

    Hello doc,

    I had protected oral and vaginal sex with a worker but before the intercourse i fingered her vagina a bit and then 2-3 minutes later i touched my bare penis to masturbate.Is there any chance to expose to hiv this way?Condom was intact after the sex.

    Btw,i did hiv duo ultra test between 13-14 days after this incident.And it was negative.I also gave blood for hiv rna pcr test at the same date.Would it be conclusive?


    • Hi,
      The negative tests (especially HIV PCR RNA) are a very good indication, but for conclusive results I would recommend one last check 28 days post-exposure with the combo test.

      • LincAnxious

        Hi doc, so I’ve had some symptoms of HIV..these came a week or two after my exposure.. 3/06/2017(June)..the ECLIA/CMIA test came back negative..this was on 16/06/2017. I’m still worried if the result is conclusive because I’m having some joint pain and muscle aches at some point…Then before I did the test, I had two consecutive night sweats…I did not have a fever though;
        so currently, after the test, I’m feeling weak(low) .Plus the joint pain mostly in my shoulders and knees

  19. Dear Dr. I had unprotected sex about 3 months ago, I have severe anxiety. I went and got an oraquick oral and blood test done at the hospital. Both results came back negative. But I’m still worried. Can you give me some insight on this and if I’m in the clear?

    • drtan

      You tested twice for HIV and both are negative. What more is there to say? What additional insights do you need?

  20. RegretfulGuy

    Hi Doctor,

    I am having hsv-1 and had a high risk exposure on 5th April

    For past 3 weeks, there’s hsv outbreak, herps alike itchy patch of rashes under my knee, on and off body temp @ about 37 – 37.4 degree and having dry cough as well

    Will it be accurate for me to take a hiv gen4 test now? As I’m worried that my current condition are signs and symptoms for hiv


  21. Eduardo

    Dear doctor, I had a risk more than a month ago, I had several acute symptoms confirmed by a doctor that sent me blood tests right away, at 24 days from exposure all came back negative for std’s and negative for HIV with 4th gen ELISA, my symptoms persisted so I waited til they were gone so I could test again, I tested again 37 days from the exposure with a 4th gen ECLIA, came back negative, I’m better now but my glands are slighlty swollen and I’m worried about Epstein barr and Lymphoma, do you think HIV is definitely not my problem or do I have to test again at 3 months?

    • Hi,
      Your tests should be conclusive and I would not recommend testing for HIV again. We would not be able to comment on EBV or lymphoma and you should consult a doctor to discuss your concerns further.

  22. Can hiv survive inside a bottle of water Base lube if someone put hiv+ substance into it before I used it?

    I had a cut on my tumb, when throwing away the lube some of the lube touch the cut. I am unsure if it’s actively bleeding.

    I have made plans to get a 4th gen hiv bloodbtest in 3 weeks…. but due to this should change and delay my plan for a 4th gen blood next week?

  23. Hello Doctor
    This is a great website. I had a low risk exposure (fingering with slight cut on finger) and was ill a couple of weeks after. I took the lab based Ag/Ab 4th gen test at 20 days and this was negative. The doctor said this looked good and I am very unlikely to be infected. Would you agree with this?
    Kind regards

    • I totally agree with your doctor. In fact, I do not think you were at risk to begin with. Officially, the 4th Gen HIV test is conclusive only after 28 days from the exposure.

      • Thanks for response doctor. I am still terrified about this though so will have to go for 28 day test. Thanks

  24. Alvarmor

    Hi Doctor,

    I’m a male.
    I went into a mutual masturbation with a woman on Marh 14th, 2017.
    I got the rapid oral test done after 14 days which came out negative and after that I had the Combo test done after 23 days having also a negative result.
    I have been feeling bad with some symptoms of Hiv early stages. Do you thhink I can see it as a definitive tesult and move on in my life?

    • Alvarmor

      Hi Doctor,

      Forgot to say that I had a small cut on the skin of my finger. Exactly the finger I introduced in her

      • I do not think fingering puts you at risk of HIV. Officially the HIV Combo test is conclusive at 28 days.

        • Alvarmor

          I did the test at 28 days and the result came out negative again. Doctor said I don’t need to repeat the test however I read in many websites that Combo test 4th generation is not conclusive at 28 days.
          could you please help me to know what’s the right information?

          Thanks a lot Dr!

          • It depends what test you had done. The rapid combo antigen/antibody test offered at our clinics would be considered conclusive at 28 days post exposure, but you will need to confirm with your own doctors about which test was done and whether they recommend any repeat.

  25. Hi Dr. Tan,

    I had unprotected sex with someone of an unknown hiv status. At approximately 19 days i had the EIA duo test and it was negative. At 25 days had a rapid that was negative and at 37days had a EIA duo which was negative. Should i be worried? And should i consider this conclusive?

  26. sam garg

    Hi Doctor, I got unprotected oral from Massage place. i am male. I got stdcheck.com 10 test panel at 6 weeks. all negative. HIV was 4th gen, can i move on in life. encounter was 15 jan and test was 28 feb 2017.

  27. Dear sir , I would like to do a comprehensive male std test at your clinic and a hiv p24 test . My exposure was 24th march 2017. May I know when is the best day to take the test .do all of the clinics provide this facility ? It will be best if you can share with me the peak periods so I can avoid these timings .Thank you!

    • Hi,
      Please come down to our Robertson Walk clinic at least 4-6 weeks after your exposure for full testing. All of our clinics provide testing but the Robertson Walk clinic is the only one that can run the HIV test anonymously. Usually Mondays are busiest, but otherwise the number of patients will be variable.

  28. Usguyworried

    Hello doc,

    I recieved blow job unprotected with private csw…i got hsv1 from this encounter..but on 30th day I got muscle spasm on my neck causing neck and shoulder heaviness which comes and goes with out meds.DOC said its due to muscle tension and stress
    I went through lab test all std 4th gen ab/ag on 35 day and 41 day both negative..according to my doctor I don’t need further tests..
    Do you see my neck pain as ARS?

    • Hi,
      No this is not ARS. Not least because you have tested negative already, please stop worrying.

      • Usguyworried

        Doctor thanks for reply,do i need further test for this episode..can I consider my results conclusive?

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