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 P24 Ag/Ab Test, Duo Test, Combo Test at our Clinic

Updated information on Rapid Anonymous HIV Combo test at our Clinics. 

Info leaflet for SD Bioline Combo Test

Info leaflet for SD Bioline Combo Test

I have been getting a lot of question with regards to the Duo test or Combo test as it is also known as.

Let’s first get some basics right:

Duo Test = Combo Test = P24 Ag/Ab test

All these terms refer to the same thing. Basically it is a test that simultaneously tests for the HIV P24 Antigen and the HIV antibody.

HIV Prevention within 72 hours of exposure (PEP) – Click Here

The HIV P24 antigen is a small piece of protein that is found on the capsule of the HIV virus. When a person is infected with HIV, these bits of protein can be found floating in the blood. The HIV P24 test is a test that detects these bits of protein. This test was first developed as a HIV screening test but rapidly ran out of favor due to the development of more advanced NAAT tests. (For more details on NAAT testing please read: http://www.drtanandpartners.com/nucleic-acid-amplification-testing-naat/)The window period for P24 testing is also very small. This test alone is only accurate for between 3 and 6 weeks post exposure. So it is a test with very limited applications unless combined with the HIV antibody test. The presence of P24 Antigens in the blood indicates a recent HIV infection.

Click here for details on getting the Combo test at our Clinics

We all already know that the HIV antibody test becomes quite reliable at 4 weeks and as good as conclusive at 6 weeks. Although most health authorities still recommend a 3 months window period. So putting these 2 tests together gives you a very powerful tool to diagnose HIV infection in as little as 3 weeks. Personally I prefer to conduct the Combo test at 4 weeks because I believe that is when the level of P24 antigen peaks in the blood giving us maximum accuracy.

In our clinic, we use the SD Bioline Rapid HIV Combo Test 2.0. It is a rapid test that takes only 20 minutes for us to get results. We are also approved to conduct this test as part of the Anonymous HIV testing Program.

The test is conducted very much like the HIV antibody test. All we need is blood from a finger prick. (For more details on Anonymous HIV Testing at our clinic please read: http://www.drtanandpartners.com/anonymous-hiv-testing-at-our-clinic/)

SD Bioline HIV Combo Test showing a positive result (2 red bars)

SD Bioline HIV Combo Test showing a positive result (2 red bars)

SD Bioline Combo HIV test showing a positive result. Note the test line is very faint. This could be due to a very recent HIV infection or the test could be false positive (1% chance).

SD Bioline Combo HIV test showing a positive result. Note the test line is very faint. This could be due to a very recent HIV infection or the test could be false positive (1% chance).

Multicentre clinical trials have shown 100% sensitivity and more than 99% specificity.

This kit has been registered with Singapore’s Health Science Authority (HSA).

So the Combo Test has many advantages including:

1. Earlier detection of HIV infection.

2. Rapid (20 minutes)

3. Anonymous

At our clinic the Combo Test costs $150.

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

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

Many women are confused when it comes to vaginal discharge.

However, often this isn’t a topic you would openly discuss with your friends or even your doctor.

You may have questions such as “ Is it normal discharge? Why does my discharge always vary in amount and colour? Should I see a doctor? When should I be worried?”. These are perfectly common and normal questions to ask as vaginal discharge varies from individual and they can be quite confusing.

Usually there is really nothing to worry about unless your vaginal discharge is associated with itching, pain or bad smell. Having vaginal discharge is normal in all women. But of course, it will be helpful to know what normal discharge is or looks like.

Click here for our New Article on Vaginal Discharge

Vaginal Environment

Before proceeding any farther, let us realize that a normal healthy vagina is never free from a type of bacteria known as ‘lactobacillus’. When balanced in amount, it is a ‘friend’ and ‘protector’ of the vagina. Its role is to protect the vagina from infection by releasing certain proteins and maintaining a vaginal pH of 4.5. Once the bacterial count decreases, vaginal pH changes and various infections of the vagina can occur. Green, yellow, gray and white, thick, cottage-cheese like discharge, usually with odor, itching and pain are signs of infection.

normal discharge

Normal and ovulation discharge

Clear, whitish, thin or thick odorless discharge are usually normal and shoudn’t be alarming. It can happen at any time during your menstrual cycle. This discharges means your reproductive organs are ‘cleansing’ the vagina and cervix, getting rid of dead cells and bacteria which is being transported by these discharges.

Somewhere around the 14th day of your cycle (i.e when an egg is released from your ovary -termed ovulation), you may notice clear colourless and elastic discharge resembling egg white. It is usually much more in amount than your usual vaginal discharge. This is a good sign for those who are trying to concieve as this when you are most fertile.

Sometimes, white and more watery discharge can be found after heavy physical activities, when you are sexually excited or sometimes when you feel extremely tired.

Common causes are Infections, Hormonal Imbalance, Vaginal Environments Changes and maybe it’s just Normal Discharge!


Menses discharge

Besides having bright red blood discharge during menses, you can also have dark brown discharge which usually occurs towards the end of your menstruation or 1-2 days after menstruation.  This is the leftover menstrual blood in the vagina which was not completely cleared. It is brown as dead blood cells turn brown. Sometimes, this dark brown discharge can also be seen during your mid cycle when ovulation occurs and is normal.



Click here for details on STD Screening for Women

Bacterial vaginosis (vaginal infection caused by bacteria) is one of the most common causes of gray, foul fishy-smelling vaginal discharge. Redness of the vulva, itching and burning sensation during intercourse may accompany. Green, thick fishy-smelling discharges are commonly caused by gardnerella infections.

Gonorrheal infections are manifested by cloudy yellow discharge often accompanied by pelvic pain and frequent urination.

Trichomoniasis (a parasitic infection) gives yellowish frothy discharge with bad odor. This is usually transmitted through unprotected sex. These infections are commonly treated with over-the-counter antibiotics, most effective one being metronidazole in forms of tablets, vaginal gel/creams and suppositories.

White, cottage-cheese-like discharge often accompanied by itching is due to yeast infection known as candidiasis.

Other type of infections that you could get which could cause abnormal vaginal discharge includes chlamydia, ureaplasma and mycoplasma.

Click here for Info on STD Symptoms in Women

If you are pregnant, consult a doctor before taking any medications. Pay attention to your personal hygiene. Changing your panty liners frequently, keeping your feminine area cool and dry by avoiding tight clothing and linen panties may help prevent from such infections.

Click here to see the full range of our HIV/STD Services


We must not overlook some other simple facts that may lead to changes in normal conditions of vagina. Decreased bacterial count and an increased vaginal pH more than 4.5 are the main culprits causing infection. You may not notice that using fragrant soaps, vaginal douching and frequent bubbly baths may be some of the causes. For those who are sexually active, sticking to one partner is the best prevention, as STDs are often associated with such infections. Pregnancy and menopause may sometimes lead to imbalanced vaginal conditions due to hormonal changes. It is then best to maintain a good personal hygiene.

Although less frequently red discharge or spotting is a more serious case. When this is noted, question yourself: Have you had any unprotected intercourse recently? If yes, this may be a sign of pregnancy and you might want to do a pregnancy test. Spotting during early pregnancy may mean miscarriages or threatened abortion. Some other reasons are vaginal tear and lacerations during rough intercourse, and, if you are more than 40, it may be due to cancers. This is the time when you should be worried and tell your doctor.


Need more advice?

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

Singapore Branches


Where to find us – here

Selected clinics are open on Saturday and Sunday.

Email: hello@dtapclinic.com.sg

All Our Doctors are Fully Certified and Trained to conduct specialised STD Screening,  STD Testing & STD Treatment and HIV Testing.

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


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

If not read more about HIV symptoms.

Or 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 feel that you are at risk, please contact us to make an appointment for the HIV testing/screening.

Our Andrology and Infection Centre at Novena Medical Center is open.

Call us at 6397 2095 now to book your 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?

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.

Consultation STD Consultation – $60.00

Anonymous HIV Rapid Test only $20.00
(not inclusive of test)

STD screening
Standard HIV, Syphilis, Hepatitis B/C, Herpes Simplex Virus Type I and II $ 200.00
Urine – Chlamydia and Gonorrhoea PCR, Monilia, Trichomonas, NSU, Mycoplasma, Ureaplasma, Urine Culture, Candida $ 280.00
Urethritis and Vaginitis
Vaginal Swab – Chlamydia and Gonorrhoea PCR, Monilia, Trichomonas PCR, Gardnerella PCR, Candida PCR, Group B StrepNSU, Mycoplasma, Ureaplasma, Direct Microscopy, Candida, Vaginal swab culture $ 345.00
Comprehensive (Male) Blood – Syphilis, Hepatitis B/C, Herpes Simplex Virus Type I and IIUrine – Chlamydia and Gonorrhoea PCR, Monilia, Trichomonas, NSU, Mycoplasma, Ureaplasma, Urine Culture, Candida $ 390.00
Comprehensive (Female) Blood – Syphilis, Hepatitis B/C, Herpes Simplex Virus Type I and IIVaginal Swab – Chlamydia and Gonorrhoea PCR, Monilia, Trichomonas PCR, Gardnerella PCR, Candida PCR, Group B StrepNSU, Mycoplasma, Ureaplasma, Direct Microscopy, Candida, Vaginal swab culture $ 525.00
Individual STD Tests
Determine Syphilis test Rapid Syphilis Test $ 50.00
Determine Hepatitis B Test Rapid Hepatitis B Test $ 50.00
Herpes Simplex Virus PCR Herpes Simplex Virus Polymerase Chain Reaction (PCR) Test $ 190.00
Chlamydia and Gonoccocal PCR Chlamydia and Gonorrhea
Herpes Simplex Virus Type I IgG Antibody Herpes Type 1 $ 40.00
Herpes Simplex Virus Type II IgG Antibody Herpes Type 2 $ 40.00
Non-Specific Urethritis (NSU) Culture Mycoplasma, Ureaplasma $ 118.00
HIV test
HIV RNA/DNA Polymerase Chain Reaction (PCR) Test $600
Add $100 for expedited results
Rapid Fingerprick Blood HIV-1/2 P24 Antigen/Antibody Combo (HIV Duo Test) (4th generation!) $ 150.00
Rapid Oral Saliva HIV-1/2 Antibody Test (Oraquick) $ 50.00
Rapid Fingerprick Blood HIV-1/2 Antibody Test (Determine) $ 50.00
PEP $2000 – $2200


  1. Kalinga

    Hi Doctor,
    I hope atleast you can give me some proper explanation. Im actually tired with this testing phase already. I had a protected exposure, and yes I got paranoid. The condom didnt break. I need an explanation on my testing, i had a duo test 3 times. One was at 2 weeks most probably on day 16. Second test was on 26.5 days. 3rd test was on 60 days.all are negative. Now my question when do exactly a duo accurate? I was freaking out that i took the second test early when it should be done at 28…..and then i thought later the better…now im confused because on the net or cdc web…its stated duo has to be taken “at 28 days”. Does it mean a duo is not accurate before 28 or after 28? Please help to explain. Im really really tired. Can i conclude HIV is not my concern

    • Dr Elaine Loh

      Your test on day 26.5 and day 60 are good indicators that you have not been infected with HIV. However, we are unable to give more medical advice over the internet. If you wish to discuss further, you can visit us here: LOCATIONS


    Hi Doctor,

    Need some information, after a low risk( vaginal intercorse with condom), I’ve tested 16 days duo ( elisa = ag-p24/ab-igm&igg not reactive), 27 days duo (eclia = ag & ab not detected)and 61 days duo ( elisa = ag-p24/ab-igm&igg not reactive) is it enough to move on?
    Your reply is highly appreciated

    • I would consider this conclusive.

      • Thanks doctor. Just one question. Do i need to repeat at 3 months?

        • I do not feel it is necessary but it is up to you.

          • Reema

            Hi doctor,
            Appreciate the reply, may i know whether has thr been a official guideline that states testing at 28 days or after 6 weeks is sufficient to exclude the hiv infection? Im asking this as too many confusing info out thr.

  3. Doc i had unprotected sex and got tested 27 days later by cmia p24 combo,which was negative. Should i take another test again to confirm as i am very worried and paranoid. Earlier i was tested positive prior to the 27 days test for clymidia. Which i was took azithromycin for. That was due to oral sex recieving around 3 weeks prior to my HIv cmia combo p24 test. Are these related in any way.. will the medication i took azithromycin 1000 mg effect my result in anyway for cmia combo p24 at 27 days post exposure. Your help is highly appreciated. Have been having sleepless nights …

    • I would consider it essentially conclusive, although we do say 28 days or more to be 100% sure. The chlamydia and treatment with antibiotics would not affect the results.

  4. hi dr Jonathan, i was visit you during the 2 of may 2018 at Robertson walk. i just get myself tested for the hiv ag/ab and hcv antibody test (igg) and all test come back nonreactive.

    1. dr can i consider myself free already?
    2. dr together my hcv pcr rna test at 5 weeks (qualitative and quantitative) test and antibody negative at 12 weeks, am i free already?
    3. dr can i move on from the exposure?

  5. Sebastian

    Dr. Jonathan,

    I had protected vaginal sex and unprotected oral (giving/receiving) with a sex worker. I took a combo duo test at 19 days after the fact but my anxiety is getting the best of me. I took another test at 61 days in which I am waiting the results.

    How confident should I be on the 19 day results?

  6. skv24

    Hi Doctor, I’m really under confusion at the moment. Can you please help me advise. I had a protected encounter with a girl. I got paranoid and googled up, and found all kind of crazy information, and even the calculation for 28 day is more confused me, as there was forum know as freedom health, where the doctor mentioned “day 1” as day of exposure. So i calculated and took the elisa duo on 17th day (as per my calculation) which came back non reactive, and went for another test on 28th day ( as per my calculation) which came back not detected method eclia. Now 3 days after the 1st test(17days), i developed a sore throat, which changed to runny nose and cough, the heavy runny nose went away after 3 days. The cough with nasal congestion is still there. I didnt have any fever to my knowledge. So can I take my 17th and 27th duo test as conclusive. To add, I did another rapid test on 37th day, which is negative as well. My doctor said 4th week regardless of day 27 / 28 the test is conclusive. Do i need to further test doctor?You reply is highly appreciated.

    • I would consider your testing conclusive.

      • Skv24

        Hi doctor,

        Appreciate your reply highly.
        I’ve done 2 rapid antibody test at day 48, came out negative as well. So can i rest easy. As both of my docs said its conclusive. Will you advise the same?

        • Hi Doctor,
          May I know why said you would regard my test as conclusive?
          All my doctors said that I should move on, but my mind and brain is at war. I saw your post that elisa can detect an infection after 2 weeks, and ive tested continously negative with duo at 17 and 27 day and have also tested rapid ab on 48 day. Can I move on doc? Please do reply i just wanna move on

  7. dr jonathan thank for your reply. however, i was tested with the hcv pcr rna at 5 weeks (qualitative and quantitative). so it be conclusive? and may i know what is the hcv window period? thanks