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 Window Period

Are your HIV tests accurate?

HIV testing may seem very complex.

This is greatly due to the testing ‘Window Period‘. That irksome time from when a person is infected to when tests can actually detect a HIV infection.

Click here to read about the Biology behind the Window Period

HIV Signs and Symptoms

The HIV Window Period and Test Accuracy

HIV PEP Post Exposure Prophylaxis

This has caused a lot of doubt and worry with regards to the accuracy of tests done.

You might even be wondering right now how accurate your tests are.

There is a lot of confusing information out there. Some people claiming a window period of 2 weeks some people even saying 10 years!

This is because HIV testing technology has developed significantly since HIV was discovered in the 1980’s.

So a lot of information out there is out-dated.

Also, not the same standard of tests are available everywhere. This has caused different governments and different health authorities to develop different testing guidelines. So the reason why the Window Period is different in Massachusetts is different from Singapore is not because humans in the US react differently to HIV compared to humans in Singapore. It is because of local guidelines.

So what exactly if the HIV Window Period?

It depends a lot on WHICH TEST was done.

The following graph was prepared based on the latest information on Testing for the Diagnosis of HIV Infection.

HIV Testing Window Period for various Tests

HIV Testing Window Period for various Tests

 

 

 

 

 

 

 

Some points to note:

1. If you are within the first 10 days of possible HIV infection (aka the Eclipse Period), don’t bother doing any tests. There are NO tests that are accurate.

NB: If you are within the first 3 days of possible HIV infection please see us about PEP.

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

2. At day 10, the HIV-1 RNA PCR can detect HIV Viruses in the blood.

Remember that the RNA PCR test has a high chance of giving a false positive result.

If the RNA PCR test gives a report of less than 5000 viral copies per ml, it is likely a false positive.

Click here for information on HIV RNA testing at our Clinics

Also, the viral load may drop to an undetectable level upon full sero-conversion.

This is because the body’s immune system may have suppressed the infection to a point where there is not enough HIV virus in the blood for the RNA PCR test to detect.

3. Between day 14 to day 20, the HIV P24 Antigen will start appearing in the blood. This can be detected with 4th Generation tests (aka Combo tests).

This is why, although the official recommended Window Period for the Combo Test is 28 days, we are very confident when a patient tests negative at 2 weeks.

Remember that the P24 Antigen level will peak at about day 28 and becomes undetectable at about 6 weeks from infection.

This does NOT mean the 4th Generation (Combo) test is inaccurate after 6 weeks because the Combo test also detects IgM and IgG Antibodies (See below).

Click here to learn more about the Combo Test at our Clinics

4. Between day 20 and day 23, the IgM Antibody starts to become detectable in the blood.

This is only detectable by 3rd and 4th Generation HIV tests.

This is the other reason why even though the 4th Generation (aka Combo) test is supposed to be conclusive at 28 days, at 3 weeks when a patient is negative, we tell him/her it is as good as conclusive.

5. Between day 28 and 48, the IgG Antibody starts to become detectable in the blood.

This is detectable by 1st, 2nd, 3rd and 4th Generation HIV tests.

This will remain detectable in the blood for as long as a person lives. Therefore, doing a Combo test not only detects HIV infections that occurred recently, it also detects infections from years ago.

Click here for HIV Testing FAQ

More things to note:

The recommended 1st line screening for HIV infection is the Combo test NOT the antibody test.

So when you go for a HIV screening test, you should be asking for a Combo test. Take note that in Singapore the Combo test costs more than an antibody test.

The essential thing to remember about HIV testing is to get the RIGHT test done at the RIGHT time.

Come see us for professional advice on which test you need to do.

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

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

Your are welcome to visit Our Doctors at Our Clinics anytime during our opening hours.

HIV_banner

Click Here for Contact Details, Address and Opening Times.
Click here to contact us

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

Call us at 63972095 now to book your treatment.

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

All prices quoted below excludes prevailing GST

We are Open on Saturdays and Sundays.

Click Here for Contact Details, Address and Opening Times.

 

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                           63972095   map

Scotts                              66942348   map

Somerset                       62620762   map

Email:  [email protected]

HIV_banner


 

If you have any questions, visit our free online forum on sexual health, HIV and STDs.More on HIV symptoms.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.We are now open on weekends.Related Articles:HIV CMIA Test AccuracyHIV ELISA and ECLIA testGetting HIV from Oral SexMore on HIV symptomsHow long can HIV live outside the body?Erectile DysfunctionPremature Ejaculation

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 $20.00-80.00
Rapid test only $20.00
(not inclusive of test)
8am – 5pm $60.00
5pm – 9pm $80.00
STD screening
Standard HIV, Syphilis, Hepatitis B/C, Herpes Simplex Virus Type I and II $ 200.00
Male
Urethritis
Urine – Chlamydia and Gonorrhoea PCR, Monilia, Trichomonas, NSU, Mycoplasma, Ureaplasma, Urine Culture, Candida $ 280.00
Female
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 $ 200.00
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

1,336 Comments

  1. Carlo

    Hi Doc.i have a protected sex exposure with the sex worker. I feel worried I took hiv test on my 59th day post exposure it came out negative (Sd bioline 3.0)
    66th day post exposure CMLIA (4TH GEN) NON reactive
    75th days post expsoure non reactive
    Is my 66 day non reactive result is conclusive? My worried is after i got my result on my 66 day post exposure hiv test i have sex with condom with my girlfriend my worry is am afraid that i may infected her.

    • Dr. Julian Ng

      Hi,

      I assume the HIV test you did at 66 days post-exposure was a Ag/ Ab 4th Generation test. If so, then the result is conclusive.

  2. Ahboy

    Hi,dr if have hiv can take work permit in singapore? And the singapore use what generation? If i have 3test 1st is at 20day ,34 day,75day all no reactive mean ok? First and second is at malaysia test ,the last is at singapore i do the work permit ,is that i ok? Or nid retest? Thk for help

    • Dr. Julian Ng

      Hi,

      Generally, if someone is on work permit and is confirmed to have HIV, the work permit would normally not be approved or it would be revoked. As for testing for HIV, when you apply for your work permit, that would have been tested. as to whether you need to be retested, you will need to discuss with your doctor especially if you have particular risk exposure.

  3. Hi Doctor,
    I met(with protection) a girl on 6th October 2017, after a way week I feel so many changes in my body , like weakness, headache(24 hours) , mouth ulcer. I waited a 66 days and went for testing HIV 1/2 (AG & AB). its came as not detected. after that also I am facing same symptoms , I just worried and again went for screaming after 160 days, its came as not detected. but still I have all the symptoms mentioned above, I can see vertical black line on my hand nails and near elbow two glands are paining, one more thing on November I bit reduced my weight now again increased. kindly suggest me what I can do further , can I go for HIV RNA test ? kindly help me on this

    • Dr. Julian Ng

      Hi,

      Your HIV results are conclusive. your symptoms are NOT due to HIV, however you should still seek further medical attention for your ongoing symptoms as they may be due to other medical conditions.

  4. Hi Doctor,

    I had protected sex with a massage lady overseas 4 days ago. I was tested HSV positive a few years back and had outbreak every now and then on my genital area. Since 2 days ago I experienced extreme fatigue, nausea, tingling sensation and numbness on my hands and feet. I would like to do a gen4 HIV test on the 14 days post exposure to ease my anxiety. May I know if the test would be a good indication as the anxiety and the current symthoms is killing me.

    • ARS symptoms will not develop after 2 days, so that can be reassurance enough. However, if you are still concerned, you can come down to our clinics for testing – 2 weeks post-exposure would be a very good indication, but for conclusive results we would advise a repeat test at 28 days onwards.

  5. Biplob ghodh

    HIV 1/2 25 days and 41 days negative conclusive at 58days no symptom

    • Dr. Julian Ng

      Hi,

      I assume you are using the 4th Generation HIV test for testing. If so, then your test is conclusive after 28 days post-exposure.

  6. hi sir..

    what is the hiv window period ?
    some doctors say window period vary confused….
    take test every 3 months I am not sexualy active.
    I am do only single exposer.
    9 months offer exposer alere combo test negative..

    pls say what is the exactly hiv window period.?

  7. Hi sir..

    I read the internet some people don’t develop antibodies in many years….this type of persons which test to detect hiv absence or percent conformation….

    The 4thgeneration hiv test 3 months accuracy 99.9 and my result negatve 17 months post exposure it’s mean 100% accuracy…

    Iam free from hiv infection..

    Iam start my new life… without hiv fear…

    Thank you..

  8. Charles

    Dr i got an question to ask as i very worried about that. As i had done alot of test and i am very tired for that ad. Or maybe you cn give me a good explaination. I had protected sex with a girl. Just done a combo test after the window period. However i was saw hep c co-infection and sero-negative. So i was really scare that the combo test and pcr rna test will no be conclusive for over come the issue. Really i feel tired to ask and seeking more test ad. Pls help thks

    • Dr. Julian Ng

      Hi,

      If you have Hep C infection, it can cause a delay in seroconversion of HIV.Thus, if you are concerned whether you could be Hep C infected, please visit a doctor for further evaluation. If you are found to be Hep C infected, then window period for testing will likely need to be extended to 6 months.

      • Charles

        Thks dr julian. But cn the 4th gen test still able to detect it? Or any test can detect it?

  9. Dr.tan..

    Plz reply me doctor your silent I’d killing me daily ur reply all the person questions y not for me

  10. Hi sir…

    Pls give me your valuable replay….
    Iam full load anxiety…..

    This year june iam get married pls help me sir….

    Iam free from hiv…

    Last question

    Thank you sir..

  11. Hi doctor tan
    I am 26 years male. I am circumcised male. I am unprotected vaginal sex single exposer w a girl. Later 9 months found she is hiv positive.

    17 months post exposure , 4th generation alere combo hiv test negative.
    My question:
    This year june I am get married make children’s happy family.
    pls clarify me I am 100% negative.

    One doctor told me hiv windowperiod 3 months to 10 years.take hiv test every 3 months..

    Iam 100% negative…
    Pls answer my question….

    Thank you your replay….

Leave a Comment

Thank you for your submission.

We will get back to confirm your appointment as soon as possible.