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HIV – Understanding the Window Period

Asian Geographic article on HIV

Asian Geographic article on HIV

The HIV window period often is the cause of a lot of confusion.

There is a lot of information on the web throwing up numbers like 3 months, 6 months even 1 year. So what exactly if the HIV window period?

To better understand this, let us take a step back in time to when HIV was first discovered. At the same time, learn a little about how our immune system works.

The HIV virus was discovered in 1983. Prior to that, it was not known what was causing the disease known as AIDS that was ravaging certain communities in the world.

After scientists discovered the existence of the HIV virus, they had to find a way to determine if a person has this virus in his body or not.

The ELISA Test and Our Immune System

In 1985, they developed a test called ELISA which is based on a very basic principle of how our immune systems work.

When our body is attacked by a virus, it will produce anti-bodies to fight the virus. Anti-bodies are unique. The anti-bodies used to fight HIV would be completely different to the ones used to fight dengue, for example, or any other virus.

So finding HIV anti-bodies in the body is indirect evidence that there is HIV virus in the body too. The ELISA test does exactly that. It tests for the presence of HIV anti-bodies.

Click here to learn about the Different Generations of ELISA

HIV Signs and Symptoms

The HIV Window Period and Test Accuracy

HIV PEP Post Exposure Prophylaxis

Imagine each virus infection is a fire that starts in the body. Each of these fires produces a uniquely colored smoke. When we see a particular colored smoke, we assume that there is that particular type of fire burning away. The ELISA tests for HIV colored smoke but does not detect the fire itself.

But there was one big problem. It sometimes takes the body a long time before the body produces enough anti-bodies to be detected by the ELISA test. In other words, the fire has to burn for a long time before it produces enough smoke that can be detected by ELISA.

This period when a person is infected with HIV and the ELISA test is unable to pick it up (the period when the fire is burning but there is no smoke) is called the window period.

This was correctly recognized to be a very important finding and rightly so because a person infected with HIV within the window period can get tested and be told he does NOT have HIV. He will then not take steps to protect himself and the people around him thus increasing the risk of spreading the disease.

Different Types of HIV Tests

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

Scientist has ever since been working on improving and coming up with new and better testing techniques and technology. There are now multiple different tests for HIV including ELISA, ECLIA, CMIARapid Tests, Western Blot, RNA PCR, DNA PCR and P24 Combo Tests. There are also multiple different manufacturers of each test. All of these tests have their own rates of accuracy, window periods and applications in the management of HIV. To make things even more confusing, there are also tests for indirect evidence of HIV infection like CD4 cell count and CD4 CD8 cell ratio.

So when you read somewhere or someone tells you that the window period for HIV is X number of months, your next logical question should be ‘by using which test?’

To know which test done when has what accuracy requires a lot of professional knowledge. This information is also constantly changing as more and more research information is published. There are also other considerations such as waiting time, anonymity, costs etc

It is still best to speak to Our Doctors who are certified and trained in HIV counseling and testing to find out which test is most appropriate for you.

Click here for Updates on the HIV testing Window Period

One thing remains constant. If you are at any risk of HIV at all, no matter how minute, you MUST get tested. But as for which test to do and when to test, it is still best to speak to a medical professional trained in HIV matters.

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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 EjaculationTestosterone Deficiency Syndrome / Andropause

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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3,525 Comments

  1. Please Dr could you reply to my question I’m so stressed.

  2. Hi docter I had a incident about 14 weeks ago.I used someone’s razor and cut myself on many places.I just wanted to know can a person catch hiv that way? He used it in the morning then I used it in the evening .I can’t remember if there was any blood on that in why I freak out.The same guy wich razor I used fingered me a week before the razor incident?Can a person catch hiv from being fingered? I was so worried and asked the guy to take a finger prick hiv test 8 weeks after the exposure and it was negative.I also got tested at week 1,3 and 4 after exposure with the p24 antigen combo and came back negative. I was still worried so I went for a pcr because I was sick and it stressed me out more but at 6 weeks the hiv DNA pcr also came back negative.For a while I was fine and then just sudden I started to stress again and went for a hiv antibody finger prick test at my pharmacy at 10,12 and 14 weeks . All 3 test was again negative. Must I test again at 6 months?

    • Please reply

    • I really do not understand your level of stress. First of all, you cannot get HIV from fingering. Secondly, you cannot get HIV from using a razor that has been used hours before. Thirdly, your partner tested negative for HIV. Lastly, and most importantly, you also tested negative for HIV. So please explain to me, with all these obvious facts that you yourself have stated, why you are still worried about HIV? It honestly does not make sense at all. Please stop being so paranoid. You do not have HIV. Move on with your life.

      • I have a sore throat for about 3 months now and a rash on my body that won’t go away that is why I am so worried and I have a headache everyday… That is the only reason why I am worried.Is the tests I did accurate at that time? Thank you for your time you are the best.

      • Sir I have done dna n other normal blood test of giv came negative. Is any chance is ther the status wil Chang plz help me I am worried I am getting married in few days

        • The accuracy of your test depends on what test you did at what duration after the exposure. You should clarify the accuracy of the tests you did with the doctor who performed the tests for you.

  3. Very stressed

    Dear Dr., I had not any sexual activity, I am married and an older guy (56). But I was to the barber’s shop than I got sick (muscle pains, sweating, weakness, throat pain) after about two months. I tested HIV antibodies rapid test NEGATIVE after 61 days from this visit. I can suspect only the barber’s razor for infection. Do I need to go for further testing? Thank you.

    • I have seen many questions about getting HIV from a barber shop. But personally I have never seen any documented proven cases. I wonder why this is such a worry. If you or anyone knows of an actual case of HIV infection from a barber shop visit, please share that with me.

      HIV Antibody tests are only officially conclusive at 3 months. So you need a repeat test even though I question whether or not you were at risk in the first place.

  4. Do, I need to take a HIV test after a deep kiss with tongues, I have a cavity that is to the gum. I have been sick since the week after the kiss.? Can you catch HIV like this?

    • Why are you so nervous about this? Kissing does not transmit HIV. Please relax and move on.

      • I guess because I have poor dental health. The internet is full of conflicting information. I will try to put it behind me. Thanks

  5. Denial

    Dear dr.
    Can ars symptoms occur after 7 week of exposure……

  6. Hi. I had unprotected cunnilingus & protected vaginal sex with a female sex worker on 12 Feb 2016.

    How high is my risk of getting infected and when should I get the rapid 4th gen combo test.?

    • Your risk is not high at all. You should get the HIV 4th Gen test at 28 days post exposure. It is actually MORE important for you to screen for other STDs like Chlamydia and Gonorrhea.

  7. Hi doc, few qn to ask.
    1) do hiv rash itch. How does it looks like.do the rash comes witb other symptoms or can be alone.
    2) i read abt the uk guideline and they said 3mths is then conclusive. I took the combo test at 5 weeks and is negative. Conclusive?
    3)

    • 3) i have throat inflamation at 8 week post exposure and pimples like spots only on my right leg which doc said is bacteria. Is the hiv related sore throat real bad as im able to drink n eat as mormal. Some website say ppl experience mild symptoms like flu. Im confused now.

      • 4) possible for the symptoms come at 8 week after exposure?
        5) possible for rash to appear on one side of the body as i read it is normally asymmetrically. Mine only occurs on right calf. No other rashes spotted.
        6) how long do the rashes last? Y do some said the ag/ab might not be detected at 4 weeks?

        • 4) Possible. ARS symptoms can appear from 2 weeks onwards
          5) Possible.
          6) This really varies from person to person. Antibody may not appear so early. Antigen appears from 2 weeks onwards, so can be detected at 4 weeks.

    • 1) Please read this http://www.drtanandpartners.com/more-on-hiv-symptoms/
      2) Combo test at 5 weeks is conclusive enough. If you are concerned, you should take an antibody test at 3 months.
      3) Again, please read http://www.drtanandpartners.com/more-on-hiv-symptoms/

  8. chemicallll

    Hello DR,
    I did PCR test at day 10 negative
    14th Day Vidas duo ultra(p24 and antibody) negative
    and 42th day Vidas duo ultra test negative.

    My question is I got cold and tonisilit infections easily( I used to smoke a lot) before I am not sure this may be considered as a weak immune system. Can my body produce antibody late?(after 42 days)

  9. Skittles

    Hello Dr.,

    Some time ago I had an exposure with a Female sex worker, we had protected vaginal intercourse and I performed unprotected cunnilingus on her, I’ve read that the risk for oral sex its extremely low, but in my situation I’ve bit myself on the side of my mouth around 30 minutes before the act, there was no blood but there was definitely some inflammation at the moment of the act.

    I did a 3rd generation blood test in a lab (Labcorp, USA) and it came back negative at 61 days (8 weeks 5 days) after exposure.

    My questions are,

    1) Does the lesion in my mouth increased the risk of contracting HIV from cunnilingus?
    2) Is my 61 days negative considered a great indicator and what are the chances of it changing to positive on my 12 weeks test?

    Thanks,

    S.

    • 1) No
      2) 3rd generation antibody test is only conclusive after 12 weeks. Day 61 is too early.

      • Skittles

        Hello Dr.,

        thanks for the prompt response.

        Would you recommend more testing based on my risk?
        I did test for all other STD also and all came back negative.

        thanks,

        S.

  10. Hello doctor, is my test conclusive at 2 months 15days with alere determine HIV1/2 Ab? Am showing almost all the symptoms of HIV like slight rash,sore throat,slight cough and mouth ulcer but I tested negative at 2months 15days. Am so worried sick. Please answer. Thanks and God bless u always. My condom broke during sex with a lady of unknown status. Help me plz

  11. Please doctor, how accurate is determine HIV 1/2 Ab after 2months 15 days . My condom broke during sex with a lady of unknown status. Please answer. Tnx

  12. Hi,

    3 days back I had possible exposure. I had sex in massage parlour which was not planned. I was around less than 30 second inside her vagina when I got scared and pushed myself out. She quickly removed the condom and flushed it out before I checked the status of condom (for tear or cut). Every thing happened so fast I dont remember exact details. Now I got nervous.
    I went to one govt authorised clinic for test (within 70 hrs), but they told me that HIV test would be more reliable if I do it after 18 days or 30 days or 3 months.
    What would you suggest me to do? I am quite stressed.

    Thanks

    • Dr Justin Sim

      I assume now you will beyond the 72 hour mark so PEP is out of the question. This means you have 2 choices. Either wait till 10 days post exposure and do the expensive PCR RNA test or you wit for 1 month and do the rapid 4th gen combo test. Both will be accurate.

  13. Sherry Lewwis

    Hi doctor.
    I was tested for HIV last month. One of the tests was an HIV 1/O/2 antibody test and that was negative. I was also test for a fourth generation screen test and that was positive. The last time I had sexual contact was 2 years ago.
    Am I conclusively hiv negative? My doctor said so but I am still worried because of the positive fourth generation. She said it was a false positive.
    Thank you!

    • Dr Justin Sim

      It is possible that the 4th gen shows a false positive but best to be sure here. You may need another test or you may need to get the HIV PCR RNA test done as this is the definitive test for HIV although it comes at greater cost.

  14. Worried

    Dear Dr.,
    I’m a male and have been tested with Elisa 4th gen. on 18 and 47 days post exposure.
    Now I’m 10 weeks post exposure and experiencing left lower leg aching with moderate knee pain, left arm aching and somethimes aching of wrists.
    The exposure was unprotected oral and protected vaginal.
    I have tested for all STDs on 18 day post exposure.

    As I’m still experiencing above symptoms, should I retest again for all the STDs together with HIV or my tests are conclusive?

    Thanks on your advise!

    • Your achy symptoms may not be related to HIV or STD at all.
      Your HIV test is conclusive. However, it is advisable to get tested at 3 and 6 months if you are worried.
      You can repeat a STD test at 3 months if you are concerned.

  15. Hi Dr,

    I’m planning to get an HIV test after 6 and 12 weeks but am only in week 2 and am constantly thinking about my chances of catching hiv from the following 2 incidents. Both occurred last week on a trip to Bangkok. I would really appreciate your thoughts as I am reading contradicting statistics on various websites:

    I had 2 episodes of vaginal sex with a Thai street worker of unknown status. I used a condom both times but frighteningly the condom slipped both times. First time, I realised fairly quickly I think though my memory is blurry and I may have been inside her unprotected for a minute or so. I withdrew and received a hand job to climax.

    The next night I was checking the condom was on constantly due to what happened the night before. I think I noticed very quickly that it slipped. Stupidly, we reapplied the same condom and I finished inside her. No apparent rips on the condom so I’m not worried about full ejaculation inside her. I think the condom did it’s job here.

    There were no apparent cuts or leasions on my penis at the time of the incidents and I had no other STD’s before the incidents. I’m a fit, healthy male who rarely gets I’ll so I must have a good immune system. Does this make a difference? The sex worker did offer a condom to start with which I suppose is reassuring but I had my own anyway. There was no friction during the sex as far as I know. In fact, she seemed very lubricated.

    I’m scared by rumoured infection and transmission rates among Thai CSWs as well as the fact that I was unprotected, even if it was only a minute or so.

    Like I say, I will take the test but is there anything you can say to stop me worrying?

    Thank you. I really appreciate you reading and replying.

    • Even if she had raging HIV and you had full on unprotected sex with her your chance of getting infected is only 1% at worst and possibly even as low as 0.01%. That is what the real statistics say. What is actually more baffling to me is since you are so worried, why don’t you get the RNA PCR test? You are at 2 weeks right? That test is 100% accurate. You don’t need to wait till 6 weeks.

  16. Hi dr tan!

    I am in very stress please help me. Your one opinion can change my life.
    My question is that i had used electric shaver after 15 minutes of other person use and it cut my skin. My concern is that if first person is hiv + and his blood on electric shaver and it cut my skin after 15 minutes of his use can hiv be transmitted to me or virus is already killed in 15 minutes. Please reply you are luke a god for me.

  17. I had a potential exposure to HIV I took a blood test around five months later it came back negative but to come in here that the person that I had unprotected oral and sex with their old partner was HIV positive could I possibly have been exposed and test results just were on a conclusive artists results were correct please cynthia HIV anxiety off of me I’m so worried now I have a boil on my private area I really need to know if I could have been exposed 5 months before I got tested in 2013

  18. Doc I had oral an unprotected sex someone bac in 2012 I tested in Dec.2013 my blood test was negative for hiv but this year in 2015 they found out that a person they was with in 2009 had hiv please tell me I have nothing to worry about because now I have a.boil on my private area an just gettin oer a really bad cold an now I have a really bad cough lingering from my cold but it’s not a dry tough I jus cough up green flem tell me I’m ok jus thinkin to much n let me know if my blood test would be accurate after five months of possible exposure

    • Dr Elaine Loh

      HIV ELISA test is conclusive 3 months. In my opinion, there is no need to repeat unless u really want to. For the symptoms that you are experiencing, best for you to visit a doctor as you may require antibiotics.

  19. Doc I had oral an unprotected sex with someone bac in 2012 I tested in Dec.2013 my blood test was negative for hiv but this year in 2015 they found out that a person they was with in 2009 had hiv please tell me I have nothing to worry about because now I have a.boil on my private area an just gettin oer a really bad cold an now I have a really bad cough lingering from my cold but it’s not a dry tough I jus cough up green flem tell me I’m ok jus thinkin to much n let me know if my blood test would be accurate after five months of possible exposure

  20. Dear dr.Tan,
    Very much appreciate your efforts to reply to all of us deling with high stress and anxiety while waiting for final test confirmation.
    Here is my story:
    On february 5th 2015. I had possible exposure to hiv having short unptrotected insertive oral sex and short protected (by condom) vaginal sex with one street girl.
    (As that was my first time to have a sex other that the one in relationship, it came out that it is the biggest trauma I’m experiencing in my life.)
    Five days later I had a really bad sore throat with some fewer for two days. It was Bronchitis like with lots of productive cough. As I went to a vessel trip these days and it was very windy, I suppose that bad weather was the reason of it.

    In the mean time, I realized that HIV ARS include fewer and sore throat and I started to worry.

    Thee weeks after exposure I had loose stools for 5 days with no fewer but colds and burns with some throat discomfort. I was very anxeous from that time so I thing that kind of diarrea comes from my stress. I lost apetite, deprssed and start to thing only about my possible HIV infection.
    Week after I developed a kind of sore throat but on low level.
    On week five, my joints started to pain (especcialy my left hand wrist and elbow). I feel I’m dehydrated too and neck and shoulder muscles seems contracted.

    I got tested at 18 days after exposure with Elisa 4th gen./ Combo (p24+antigen) ane it came out negative.

    To summerize, how do you see the mentioned test result and does my symptomes look like the ARS ones?

    Very many thanks on your reply. After readig hundreds of sites and forums on the web I found out to be very comfortable with information you are posting on your site. Especially the ones dealing with the symptoms and window period.
    Take care and continue to do your job in the way your doing so far!
    Bob

    Three weeks

    • First of all your symptoms do not sound like HIV ARS. Secondly, I am a bit confused about the dates. Your exposure was on 5th February. This actually puts you at just a few days shy of 7 weeks. So why don’t you just go get another Combo test now and get this over with.

      • Dear dr.Tan, as adivesed I have made the Elisa Duo 4th gen. test at 47 days after exposure and it is negative. Following my infection risk, same test negative after 18 days and symptoms I feel, can I consider the results almost final?
        I’m still having some loose stools lasting now for 4 weeks and I feel pain in some of my joints and muscles. Gums around few teeth are recessed but no sign of blood or gengivitis.
        May thanks on you answer!

  21. hi dr i had sex with a csw about 2 months

  22. Hi Dr Tan,

    I had protected sex with a sex worker. About 30 sec unprotected oral sex.
    After that I found out she had flaky fingers. Worried that she might be HIV positive.

    Did a rapid combo test at 12 days past exposure and it was negative. At 3 weeks I got peeling skin on my palm and fingers. I am very worried. Is the combo test accurate at 12 days?

    Thanks for your time doc
    Worried

    • I have never heard of flaky fingers as a sign of HIV. For more details on early symptoms of HIV click HERE. A combo test at 12 days is indicative but absolutely not 100% accurate. For more details on HIV window period click HERE.

  23. Jimangwe

    Is pcr dna qualitative test result conclusive at 3 weeks from Hiv exposure while on Pep?.

    • No it is not. Officially the only conclusive test for patients who have taken PEP is an antibody or combo test at 3 months from exposure.

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  1. HIV Treatment | HIV - […] Understanding the HIV Window Period […]
  2. HIV 4th Generation Test Singapore | HIV - […] HIV – Understanding the Window Period […]
  3. HIV Post Exposure Prophylaxis | HIV - […] HIV – Understanding the Window Period […]

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