Question
What different tests are used to test for HIV?
4 October 2011 • Related: All topics, HIV testing
Answer
There are three types of tests that can be used to diagnose HIV.
i) Antibody tests – window period: from 6 weeks after exposure (i.e. rapid, Tri-Dot and Centaur tests)
The most common test for HIV is an antibody test. This tests for a persons immune response to having come into contact with HIV. An antibody is a protein produced by your body when it recognises an infection.
The main antibody test is called ELISA (Enzyme-Linked Immunosorbent Assay). If blood tested is from a finger prick, then ‘rapid’ tests can give the results in 10-30 minutes. If the blood is taken with a syringe, it is usually then sent to a lab, and results can take anything from a few hours to a few weeks, depending on the urgency of the sample, and procedures of that clinic.
If this result is negative or non-reactive, then you are HIV-negative.
If the result is positive though, this does not mean that you are HIV-positive. A small percentage of people can test positive with ELISA who are not HIV-positive (called a ‘false-positive’ result).
All positive results need to be confirmed by a second, more sensitive antibody test called Western Blot. The Western Blot test takes longer (usually a week or so) and is the most accurate at identifing genuine positive results. The Western Blot test used to confirm a positive result is 100% accurate.
HIV antibody tests do not work as soon as you are infected. This is because it usually takes several weeks to generate antibodies to HIV. This is called the ‘window period’. Most people generate this response within 4–6 weeks, but approximately 5% of people take up to 3 months. Very rarely it can take longer.
The result of an antibody tests therefore only tells your your HIV status three months prior to the test. This is why people are advised to re-test three months after the exposure if you test at 4-6 weeks, or to wait three months before taking an HIV test.
Taking an antibody test less than 4 weeks after exposure will not tell you very much. You need to wait until at least 4–6 weeks after the exposure.
You then need to confirm a negative result with a second test three months after the exposure.
This confirmatory test is to cover the small chance (less than 5%) that you may not have developed an antibody response this early.
A modified ELISA tests called RITA (Recent Infection Testing Algorithm) can indicate whether the infection is likely to have been in the previous six months. Detuned means that the test has been modified, so that it is less sensitive.
It is provided to every NHS clinic free by the public health laboratory based in Colindale. In the UK this is recommended with every positive HIV test. The results given a good indication that the infection is recent but are not a guarantee. This is now referred to as RITA .
RITA used to be called STARHS (Serological Testing Algorithm for Recent HIV Seroconversion). A technical review of STARHS is at this link.
ii) p24 antigen tests and combined antibody/antigen tests (ie Duo tests) – window period: 3–4 weeks after exposure (UK clinics generally say 28 days).
Some HIV tests combine an antibody (Ab) test with an antigen (Ag) test.
An antigen is a name for genetic material caused by a virus or other infection. In these tests the antigen being tested is p24 (protein 24), a major protein that is part of HIV.
p24 is detected 2–3 weeks after infection – before antibodies are produced, but not really afterwards – and p24 levels only stay high for the next 1–2 months.
p24 antigen tests can be used 3–4 weeks after exposure – so can give an earlier result than an antibody test. The are combined with antigen tests because the window period that p24 is detected is very short.
As with antibody tests, a small percentage of people may have a delayed response to HIV so people using this test four weeks after any potential exposure are routinely recommended to confirm a negative result three months later.
iii) Viral load tests (PCR) – window period: 1–4 weeks after exposure
Viral load tests are also called PCR (Polymerase Chain Reaction) tests. They either test for HIV RNA or HIV DNA.
Rather than look for an immune response, they look directly for HIV, usually in a blood sample. In a new infection, viral load can reach very high levels within a few weeks of infection. More rarely this can be within if few days.
Viral load tests are not approved for diagnosing HIV testing.
However, viral load tests are sometimes used in specific circumstances. This is usually after a very high risk or traumatic risk, especially if several symptoms suggest seroconversion. In the presence of symptoms, a negative viral load test is useful. It can rule out HIV because symptoms caused by HIV seroconversion would by definition need viral load to be both high and detectable. A negative viral load test can reduce initial anxiety and worry until an HIV antigen test can confirm there is no infection.
Viral load test are neither approved or recommended for routine HIV testing by people who just want to test more quickly than the four weeks recommended with an antigen/antibody test. They are less accurate (actual infections can easily be missed), more expensive and require more complicated laboratory technology.
After infection, viral load is usually very high within the first 1–2 weeks, and so this test can be used to confirm a suspected early infection.
In adults, viral load tests look for RNA and are only usually done when there is both:
- a history of recent high risk exposure (ie condom break with a known HIV-positive partner); and
- symptoms consistent with HIV seroconversion (fever, extreme tiredness, heavy ‘flu-like illness etc).
Viral load tests are also used in babies born to HIV-positive mothers, and test for DNA. This is important to know to decide on whether the baby needs early treatment. Because a baby carries his or her mothers anitbodies for the first two years, antibody testing is not useful until a child is around two years old.
Updated: October 2011 (original answer January 2008).
Answer: Simon Collins
Comments
hari • 20 January 2008 6:57 am
Tri-dot is a good test for HIV, it gives correct result
dr upadhyay • 28 August 2008 9:14 am
Why is window period is called so, what is meant by “WINDOW”?
Svilen Konov • 12 September 2008 2:44 pm
The term ‘window’ or ‘window period’ refers to a flexibility with time, where you should still get the same result. For example, you may aim to take your meds every day at 10pm. It probably doesn’t make much difference if wou sometimes take them at 9.30 and sometimes take them at 10.30. So in this example you have a window period of an hour.
The use of the phrase probably is a shorter version of ‘window of opportunity’ which referred to a short period of time in which to do something. A ‘launch window’ referred to the short time that space rockets had to launch in relation to ground weather and getting into the right orbit etc.
The tests above are only sensitive for specific periods (ie from 1-3 weeks) so that time is called the window.
It may also originate from how a window provide the only break in a wall when you can see though. You have to use that point to get the information you want.
JAMAL • 3 June 2010 10:25 pm
My wife recently fell pregnant, as a normal routine check-up I was advised to take a HIV test for the safety of our baby. The test was done using a finger-prick test and the results came back positive.
My question is, could there be a chance that the diagnosis was wrong? How accurate are the finger-prick tests? What other test can I do to confirm my status?
Charlotte Walker • 3 June 2010 10:26 pm
Finger-prick tests are generally over 99% accurate 3-4 weeks after a possible exposure. If your test has come back positive then I’m afraid there is very little chance this result is wrong. If you still wish to confirm your test then you can always get a second test done.
If your wife is also HIV positive then the good news is that you have discovered this in time for you and your wife to protect your baby from becoming infected. For more information on what to do if you are pregnanct and recently diagnosed please follow this link.
JAMAL • 3 June 2010 10:27 pm
Does the window period apply if you have a positive test result?
Charlotte Walker • 11 June 2010 2:35 pm
If the test is positive then the window period does not apply.
shadrack pillay • 11 October 2011 6:30 am
i had 2 rapid test, one in june and one in october. Both were negative. I got cut with a staple from a hiv+ patients chart. Doc has done a pcr. Should i wori
Jose • 11 October 2011 6:58 am
I slept with a girl that I feel is HIV positive after knowing much about HIV. I had protected sex with her for about a month but my condom slipped once when I was with her. I took a test after 6 weeks and it turned out negative. But I’m scared now because I have a swollen lymph under my arm, and mild thrush. I’m freaking out and scared to take a test. Please help out….
Jose • 11 October 2011 7:03 am
Please help me coz I’ve not been able to sleep since June and I’m sooooo scared to take the test right now.
Simon Collins • 11 October 2011 2:52 pm
Your level of anxiety that makes me concerned that you are allowed to work anywhere near HIV-positive people.
Instead of wasting resources with this nonsense about PCR testing you should have counselling to understand the definition of risk.
Yes, you should worry.
taliana • 14 October 2011 1:54 pm
i had unprotected sex and after 1 month HIV test was negative also after 3 and a half month i tested again and was negative again now after 4 months i had sore troat should i worry?
Thaps • 17 October 2011 6:00 am
I started havin unprotected sex with my gf in June 2011; we went for testin on the 14th October 2011; four weeks after exposure; my test came back negative and hers positive; how possible is this? Does mean that maybe the tests could not detect mine as yet? Very confused and scared!!
Simon Collins • 17 October 2011 7:08 am
It sounds like you have been lucky in not having caught HIV – you will need another test in a couple of months to confirm this.
Not every exposure leads to an infection.
Anita • 18 October 2011 4:37 pm
Could blood in urine possibly mean that contracted hiv? Pleas help me! Thank you!
Simon Collins • 19 October 2011 4:21 pm
Blood in urine can be common. Sometimes this is not serious and sometimes it is related to an infection. Any symptoms should be discussed with a doctor. This is not by itself an indication of HIV.
Simon Collins • 19 October 2011 4:45 pm
Most people who are worried about testing often have a very low risk of HIV. So the worry is affecting your life and the only way to know is to test.
Millions of people take an HIV test every year and most results are negative. If you are positive then the early you know the earlier you can take steps to look after your health and the health of your future sexual partners.
Simon Collins • 19 October 2011 4:47 pm
You took a test once and the negative result then makes it far more likely that you are negative than positive. To know this for certain you need to test three months after your last risk.
You health symptoms are therefore unlikely to be related to HIV.
Anita • 21 October 2011 4:34 pm
Thanks a lot for your reply i really appriciated ! I spoke to my doctor yesterday as you said and he told me that blood in urine has never nothink to do with hiv but im confused because on internet many sites says that one of the resons could be std? I allwready been told in the gum clinic that i have an uti but as it never happend to me before (blood in urine) and only happend 9 days after exposure is hard for me to belive it if you undrestand what i mean. I also lost more then 2 kgs in two weeks after exposure? Its been nearly 6 weeks now and i havent experience any other symptoms. i had a rapid test done a ten 10 days and then another test that takes time at the lab at 25 days both negative and ive been told by the gum clinic that i dont have to come anymore.. Thanks alot for your help !
Simon Collins • 21 October 2011 6:00 pm
Please see our FAQ page on testing for further information and to answer all these last questions above.
http://i-base.info/qa/faq/hiv-transmission-and-testing
Anita • 21 October 2011 6:49 pm
Is 25 days still more then 95% accurate? My doctor said that testing after 25 days is very accurate and that i don’t need to test again .. Im so confused.
Simon Collins • 21 October 2011 8:39 pm
We provide information based on UK (BASHH) guidelines).
These say that a 4th generation test will detect about 95% of infections at 28 days after the exposure. A confirmatory test is recommended three months after the exposure to pick up the 5% of people who take longer to generate an immune response.
No doctor can say that the repeat test is not needed.
However, many people test when they really have not been at risk and so this might be the explanation.
rinah • 22 October 2011 10:36 am
I had unprocted sex, and tested in july, august, september and lastly in october they all became negative how long should i wait again to get tested for the last time.
Need answers im freeking out.
Jeffrey • 22 October 2011 1:27 pm
HIV DUO Ultra test at 6 months is reliable? It’s showing negative. pls if not i am going to take HIV antibody test again. Help pls.
carlos • 22 October 2011 9:35 pm
i had a sex with girl who is hiv positive….it was protected but condom broke. i changed the condon as soon as i relaise ( prox 30 sec) and i done 4the genaration test after 3 weeks and after 10 weeks and both came negative… should i worry ?
many thanks
Simon Collins • 25 October 2011 11:41 am
As in the comment above, we provide information base on UK (BASHH) guidelines).
These say that a 4th generation test will detect about 95% of infections at 28 days after the exposure. A confirmatory test is recommended three months after the exposure to pick up the 5% of people who take longer to generate an immune response.
No doctor can say that the repeat test is not needed.
However, many people test when they really have not been at risk and so this might be the explanation.
Thaps • 25 October 2011 1:38 pm
Thanks for the answer; I mean in South Africa we are still using Elisa; is this still 95% accurate after 4 weeks!!
carlos • 27 October 2011 1:49 am
please im asking again…please comment on this from ur experience please
i had a sex with girl who is hiv positive….it was protected but condom broke. i changed the condon as soon as i relaise ( prox 30 sec) and i done 4the genaration test after 3 weeks and after 10 weeks and both came negative… should i worry ?
many thanks
Thaps • 28 October 2011 10:35 am
Like as i said i tested negative in 4 weeks after exposure and my girlfriend tested positive, i tested again (with Lab blood sample) in 6 weeks after exposure, it came bace negative again; i am relieved a bit, however, what are the chances that my test my come back positive in 3 months?
david • 4 November 2011 10:15 am
I am positive my cd4 was 317 and now my cd4 and cd4cd8 ratio 867and 0.88 respectively after 6 months of medication. Since i knew i was infected i still have unprotected sex with my partner. Does it have a risk continuing unprotected sex with my partner?
carlos • 6 November 2011 2:58 am
hi its me again..i recenly said i done 4th genaration test after the risk 3 week and 10 week( both results came all negative)…but….
..i just found out that when i tested for hiv it was 11 weeks after the risk( not 10 weeks )
and all std came negative….
so is this results safe enought ?
Naomi • 6 November 2011 4:07 am
Hi,
I recently had unprotected sex with a man who has had many partners. He did not ejaculate. In the following week I had a sore throat and fevers. My doctor suggested I get a viral load test done as these symptoms are a bad sign. I had this done 10 days after sex, the test came back that the virus could not be found in my blood. I have read on your page that if you are showing symptoms of hiv seroconversion than the amount of hiv in blood must be detectable to a viral load test. Was 10 days too early to check or should it be accurate at this time . if it was caused by hiv then the virus should have been detectable in my blood?.. I am assuming my symptoms must have been caused by something else. How right am I to assume this? I will be getting an anti body test when it has been 12 weeks but I am still really worried even though I had the negative viral load test, as the symptoms were really weird…
jeee • 6 November 2011 11:41 am
Hi I’ve had protected sex with a woman that I paid to have sex with me 4 weeks ago and took an HIV1/2 antibody test that (rapid). That was negative…the condom was intact and the same condom was used for oral and vaginal sex. Can I rely on the 4 week test? Is there a possibility that coz the same condom was used for oral and viginal sex I’m at higher risk? Pls help I’m going mad.
Simon Collins • 6 November 2011 2:45 pm
See this link for information on testing and transmission and to answer all these last questions above:
http://i-base.info/qa/faq/hiv-transmission-and-testing
John • 9 November 2011 12:11 pm
I m hiv positive and i had sex with my wife before 1 month. She is pregnant now. I got her hiv status negetive by tri dot antibody test after 1 month since last exposure. I am on ART meds for last 3 months. Is she safe. I am worried . Plz help me.
Simon Collins • 10 November 2011 7:42 am
Hi
There negative result after one month is clearly good news and should calm your main worries. Your wife will still need to have a second test in another two months in case she is one of the 5% of people who take longer to generate HIV antibodies.
HIV is difficult to catch sexually so someone is always more likely not to catch HIV than to catch it from one exposure. Being on treatment would have reduced this risk, but this mainly happens after someone’s viral load has become undetectable. Sometimes this happens within the first month or two, but guidelines refer to someone having an undetectable viral load for more than six months.
Your wife will be more vulnerable to HIV during pregnancy, so always use condoms if you are sexually active during this time.
Simon Collins • 10 November 2011 7:55 am
The is good results from studies that having an undetectable viral load dramatically reduces the risk of heterosexually transmission from penetrative vaginal sex. There is still very little data to know how low these risks become.
There is also no data on the impact of treatment on anal sex (gay or straight) which carries a higher risk compared to vaginal sex (other factors being equal). The risk is still likely to be reduced but this is unlikely to be to zero.
The reduction in risk comes once viral load is undetectable on treatment (not just being on treatment).
Does your partner know you are HIV-positive? This is not something you can decide on their behalf.
Simon Collins • 10 November 2011 8:11 am
Great. Early negative results are good news and should help with anxiety if you are worried about recent risk of infection. The chance of a late positive result is low, but you still need the three month test to confirm this.
Simon Collins • 10 November 2011 8:32 am
Early negative results are clearly good news but the FAQ page discussed why a test a 3 months is recommended in UK guidelines.
Simon Collins • 10 November 2011 8:34 am
If the Elisa is an antibody only test then it is probably a bit less effective at 4 weeks. Either way, the confirmatory test at 3 months is recommended.
John • 10 November 2011 3:05 pm
Thank u, she doesn’t know my status and i am not in such a situation to tell her…. What should i do? My cd4 count was 359 before starting ART.
Simon Collins • 10 November 2011 3:30 pm
I think you have to find a way to talk about this. This is especially the case if you are having unprotected sex.
Saurav • 11 November 2011 5:19 am
I had sex with a woman on in September. I tested at 6 weeks and approx 8 weeks with the “Tri dot” test it was negative. Can I go for another test. The lab assistant gave me my result after 15 minutes.
He might test my blood sample with the HIV kit only. Is this accurate……
Simon Collins • 11 November 2011 6:00 am
The early results are good news but in the UK guidelines recommend have a final test three months after any exposure.
John • 11 November 2011 10:16 am
Hi, what diet should I take to keep myself healthy.
Simon Collins • 11 November 2011 10:30 am
Hi. If you are HIV positive then a balanced diet should give you all the nutrition you need. This should include eating vegetables and fruit, white meat (chicken) and fish in preference to too much red meat. Advice is similar to a healthy diet for HIV negative people – ie don’t eat too much fried food, or fast food, or other foods with a high sugar or salt content. This, alsong with keeping active, will help you in the long term.
fifi • 13 November 2011 4:54 am
my friend tested HIV positive a week ago but both her boyfriends tested HIV negative how possible is it that its a false positive and after how long can she test again.
Simon Collins • 13 November 2011 12:00 pm
If the positive test was carried out while she was waiting (ie a rapid test) then she can retest straight away. She is not HIV positive until a laboratory test confirms this.
If the result was from a lab test then one of her partners may need to retest or she could have caught it from another partner.
A more unlikely possibility is that she may have been HIV positive from birth, but it is unusual to survive into adolescence and adult life without previous symptoms.
payman • 13 November 2011 4:50 pm
hi mij naam is payman ik had een relatie met een meid 3 maanden later zij ging testen zij is hiv positief in afgelopen 6 maanden ik heb 7 negative test ik word gek help please
Simon Collins • 13 November 2011 4:55 pm
Hi
Wij kunnen enkel vragen in het engels beantwoorden. Indien u HIV negatief na drie maanden dan u hebt getest hebt niet HIV.
syaq • 14 November 2011 10:09 am
hye, i did a lot of mess before this, but really stop it at early july. since mid july until now, i experience fatigue, rashes all over the body, headache, swollen lymph nodes, sore throat..
i just did eclia hiv 1&2 ab/ag and got negative result. its already 4 months since then. do i need to retest?
Simon Collins • 14 November 2011 10:35 am
UK guidelines say that a negative test after three months is good enough not to need to retest.
Thaps • 14 November 2011 4:07 pm
Iv done a rapid test at 8 weeks now; it came back negative; atleast anxiety is goin away; howver; my partner still battlin with the fact that she’s positive!
Simon Collins • 14 November 2011 4:30 pm
Thanks – good to know – great that you can support your partner now through what is always a difficult time.
Brian • 16 November 2011 4:25 am
I am currently living in nagoya, japan and I do not have all the testing resources that would be available in the UK. On October 15th a had a very high risk exposure with a Thai woman who I later found out to be transgendered. So, 4 weeks later I was tested with a rapid blood antibody test called ‘Dynascreen’ (immunicromotography). The results came back negative but i still have anxiety because i know that 4 weeks isn’t very accurate. I have not been able to locate a ‘duo test’ here in Japan, However at different clinic here I just took an antigen test at 32 day mark and I am waiting on the results. If the results from the antigen test also come back negative will the results be considered conclusive or near conclusive?
Simon Collins • 16 November 2011 4:30 am
No. you will need a confirmatory test at three months. The early results are still good news though.
jimmyj • 16 November 2011 6:39 am
Hi i was engaged in an unprotected vagina sex. 32 days later i went for a complete std and hiv using elisa ab test. I had a non reactive result for hiv but sadly i was diagnosed with herpes type 2. i like to know the accuracy will still maintain regardless of which country i am in. i m from malaysia nt sure which generation test they are using..
Simon Collins • 16 November 2011 7:00 am
You will still need to have an HIV test at three months to confirm the HIV test results. This can be third or fourth generation so the type of test is not that important for the three month test.
Gerald • 16 November 2011 7:56 am
Hi, I had a 4th generation test 7 weeks and then at 8 weeks after exposure – Both were negative. However worried about some symptoms like nausia, aches and dry cough. Should I worry and continue testing?
Simon Collins • 16 November 2011 9:15 am
Your negative tests are good news, but you need to confirm this will a test at 3 months.
Your symptoms are unlikely to be unrelated to HIV. If they were caused by HIV your test would have been positive.
Michelle • 16 November 2011 9:52 am
2 weeks back I slept with an HIV pos man and I was negative but he didn’t come inside. Today I went to do rapid test and syringe test for lab. The rapid test came back negative,does that mean if the lab test comes back negative I won’t have to worry about having HIV in my body. Very scared.
Michelle • 16 November 2011 10:00 am
Thanks for your reply. For two days I’ve been taking Truvada. Will this help to reduce the risk of having hiv ,or will it clear it out if the intercourse took place in 2 weeks,without ejaculation.
Simon Collins • 16 November 2011 11:00 am
You need to have a test at 4 weeks and then again at 12 weeks. Just because your partner was positive does not mean you will catch HIV. The risks from one exposure are low. You are still likely to be HIV negative but need the tests to know this.
Taking Truvada this long after the exposure will bot have any impact of reducing the risk.
Thaps • 16 November 2011 6:11 pm
Hi Simon;
I know CDC still recommends 3 months window period; also Health Ministry in South Africa; but have you ever saw negative 6 weeks turn positive later? The whole thing I blv is causin unnecessary anxiety; I blv that the research was conducted on the high risk ppl and almost all tested positive between 6-8 weeks; why can’t CDC reduce window period to 8 weeks instead!!
Simon Collins • 16 November 2011 6:30 pm
The three month test is need because some people take three months to develop antibodies. If this was the case and you went away thinking you were definitely negative, you might infect other people.
Zeres3 • 16 November 2011 7:54 pm
I recently had a condom slip while having sex with a women in Mozambique, It was only 3 – 5 minutes or until i ejaculated when i found out that it had slipped. I went to the bathroom where i rinsed it and ended our encounter. After two weeks i decided to do an ELISA duo test at the local clinic and it came back negative. After 6 – 7 weeks i did another test and it came back false positive. What are the chances that i am infected?, after such an incidence.
Simon Collins • 16 November 2011 9:04 pm
Your answer on accuracy of tests at 4 weeks is on the FAQ page here. It is good that your results so far are negative. A test at week 4 will pick up 95% of infections and a test at week 12 will pick up 99.99%. A test between will be somewhere between these figures.
John • 17 November 2011 6:10 am
Hi sir, i want 2 know that is tridot test reliable after 01 mnth of exposure.
Simon Collins • 17 November 2011 6:30 am
At one month this test will pick up 95% of infections. A confirmatory test is needed at month three will pick up more than 99.99% of infections.
Your answer on accuracy of tests at 4 weeks is on the FAQ page here.
Francis • 21 November 2011 6:44 pm
I appreciate and feedback given. I had unprotected sex back on September 9th 2011 whilst on holiday with a 21 year old female student. We were both extremely drunk and this didn’t last long. The next day when I came back to England from my
Holiday I met up with a mutual friend. She came back to mine and we had protected sex for approx 20 mins. However, she for sum reason ‘accidentally’ takes the condom off but I didn’t know at the time and I continued to penetrate for less then 5 mins until I felt no condom. I do not know the status of these two women.
In late Oct, (7 weeks after poss exposure)I developed a slight fever lasting no longer then two days, night sweats for one night, tiredness, sore throat, muscle aches. Nearly all the ars symptoms! I went for a STD test on that week, came back positive for chlaymidia but negative everything else. In the gym few days later I noticed my lymph nodes in my groin either side are slightly swollen, not too much and they don’t hurt. I also found by my belly button 7 or so red small blotches. U can imagine my anxiety now. Went for a rapid HIV test at 8 weeks-negative. Doctor also did not think my blotches resembled that of a HIV rash. I will test again at the 3 month window early December.
1.do u think given what I’ve told u n the symptoms I’ve explained that I’m likely to
Test positive for HIV?
2. Can the treatment that I had for chlyamidia affect the 8 week rapid HIV test?
3. Is it possible for my chlaymidia infection to have caused the slightly swollen lymph nodes in my groin?
All my symptoms just seem too coincidental to be anything else but HIV. I can’t sleep properly at night and concentrate at work. Worst few months of my life. Appreciate the feedback.
Simon Collins • 23 November 2011 5:19 pm
Your early negative results are clearly good news. UK guidelines recommend the test at three months for the 5% chance that ‘if’ you were infected your body takes longer to generate an immune response.
You are worrying out of proportion to the risk, though this is a very common reaction following a single low-risk exposure.
Your doctor is giving you good advice. Your other questions are answered on the FAQ page.
I you would like counselling or information on testing please contact the THT.
payman • 24 November 2011 3:52 am
hi, i meet a girl on febriuari 2011 we got unprotect sex till mei 2011. She got a HIV test and she is HIV positief. I got a test 2 week 6 week 9 week 12 week en 24 week negative. I am scared i am gonna crazy pleas i need help i am 27 year old i life in Holland please help
Simon Collins • 24 November 2011 5:00 am
Hi
I am sorry to hear about your partner. How is she coping with the result of her test?
You have been lucky and are HIV negative. The test at 12 weeks confirmed that you did not catch HIV.
Not everyone who has sex without a condom will catch HIV, even if their partner is HIV-positive person.
The risk per exposure is likely to be less than one in 1000 (less than 0.1%) and maybe much lower. It only takes one exposure to become infected though, so this involves balancing a low risk event with high consequences should it occur.
You have been lucky and should be pleased with this rather than worried.
Francis • 24 November 2011 6:32 am
Appreciate the response simon. Thanks very much. My 12 week test will be early December so fingers crossed. Gd luck to anyone else out there anxiously waiting for
These results
Alien • 24 November 2011 3:42 pm
I had sex before 25 days exactly in abu dhabi, united arab emirates, while I was having sex I felt that’s the condom was broken, after 5 days I felt I have fever, flu while on I did elissa tests after 6 and 17 days which were negative, now after 25 days I feel I have sowllen. Any possibilities that I have HIV?
Simon Collins • 24 November 2011 4:07 pm
After unprotected sex there is always the possibility you may catch HIV. It is a small possibility, but of course that is there. This is why condoms are so useful. It is also possible you have a cold or viral infection a few days after having sex. The early tests will tell you nothing. A test at 4 weeks after the exposure will pick up 95% of infections and a second test after three months will pick up the 5% of people who take longer to develop antibodies. Please se the FAQ page for more information.
payman • 24 November 2011 10:45 pm
hi de heer simon colins.sorry my english is not good .my girfriend is shy is very opset shy test op 16mei 2011 positief i had sex wit haar on maart tell 10 mei onprotect i test 8 time negative but i am stil scared i can not word iam sitting home al 6 months i am gonna crazy .i am goning for test after 3 months again i dont know maybe i have hiv i dont know some peopel told mee hiv can be after 1 year after 2 year can be find on ur blood i dont know maybe i have luck i dont know .thanks de heer simon .
Simon Collins • 24 November 2011 10:50 pm
After 8 tests, you are negtive and do not have HIV. You are worrying too much about this and should get on with your life.
Alien • 25 November 2011 3:14 pm
Dear doctor ,
Could you please answer me on the below questions :-
1) Is it possible to have flu after a week from being infected with hiv !?
2) Does 17 days test , is good sign for not being infected !?
3) Normal is it fine for someone have flu and after two weeks be infected again !?
4) Does 25 days test , is also really good sign for the not being infected !?
5) What are the first signs for being infected with aids !? And when does it appear regulary !?
Plz answer me quickly , I feel so down
!
Simon Collins • 25 November 2011 3:30 pm
We are not doctors and your test centre should have given you this information. A negative test at 25 days does not guarantee you don’t have HIV, but it does mean that your symptoms are not related to HIV.
Information about testing and risk is at this FAQ page.
http://i-base.info/qa/faq/hiv-transmission-and-testing
Krugar • 25 November 2011 6:51 pm
I had protected sex and also a oral sex involved (from my side).
I was tested negative after 24 day.
4 and 3 generationt test.
EIA anti HIV 1/2/0:NEG
HIVP24Ag: NEG
3 weeks after test i got a sore throat. I was also got some rashes on my back and chest. I have to say that in that time i was on holidays. It was very hot and humidity was high. There was an air condition in room and my skin is very sensitive to sun. Maybe thats way i got those problems with throat and skin. Because after 2 days problems have disappeard. I took 2 anti allergic pils for my skin and some pastile for my throat.
After that i have got no problems. The only problem is my head.
I am still worried as hell.
I have been also tested negative for chlaymidia.
Are my concerns needless?
Simon Collins • 25 November 2011 7:00 pm
You were not at risk from HIV from what you describe. A condom is protective and giving oral sex to a woman is not a risk.
Alien • 26 November 2011 8:23 pm
Dear doctor ,
I did elisa test after 26 days and it came bak negative , could you please give me your fedback regarding that !?
Thanks ,
Alien
Simon Collins • 26 November 2011 8:30 pm
Information about testing is on this FAQ page.
http://i-base.info/qa/faq/hiv-transmission-and-testing
Thaps • 30 November 2011 8:30 pm
Hi Simon;
Like I said abt my girlfriend tested positive and am still negative after 10 weeks exposure; I was at my doctor today to collect my test resuts a 4th generation after 10 weeks which came back negative; my blood type group was tested and confirmed to be O Negative; my doctor said that this blood type has got resistence to some virus or one maybe infected but can’t produce antibodies; do you know any link between Hiv and O negative blood type? I’m now confused!
Simon Collins • 30 November 2011 9:24 pm
HIV tests work for all blood groups.
Stefanie • 1 December 2011 3:57 pm
Hello everyone. Just got tested at 82 days with the INSTI finger prick test. Is this test relaible? Do i need further testing? Oh and i also got tested at 56 days with the DOU test. Results were negative. Thanx a lot
Simon Collins • 1 December 2011 4:00 pm
Information about testing is on this FAQ page. Although 82 days is pretty close to 90 days, and negativ eat this time is good news, guidelines in the UK say 90 days.
http://i-base.info/qa/faq/hiv-transmission-and-testing
Stefanie • 1 December 2011 5:03 pm
Sorry forget to say it was negative
ozzy • 2 December 2011 3:17 am
hi i had a risk..broken condom..and i have tested (dou test) 3 week 11 week and 17 week after the risk and all came negative ??am i hiv free?
Simon Collins • 2 December 2011 3:30 am
Information about testing is on this FAQ page.
http://i-base.info/qa/faq/hiv-transmission-and-testing
juan • 4 December 2011 6:58 am
I once did a rapid test @ a friends dat came out reactive(,we den used another rapid test kit dat came out negative….following dat I did several rapid tests using d same kit dat was reactive, on d same day and dey were all negative…I went to a lab a few days later where my serum was used for d same rapid antibody test and it was negative…two and three months after I repeated d same rapid antibody test and it still is negative…should I still continue testing…I am still worried
juan • 4 December 2011 7:09 am
In essence I did a rapid test @ a friends dat came out reactive…I used anoda kit and it was negative,went back later to use dat same kit(not from my friend) and it was negative,went to a lab where serum was used this time around with that same kit and it was negative…two and three months later tests done with d same kit(a rapid antibody kit) have been negative….I am worried and confused
Simon Collins • 4 December 2011 9:15 am
Lab tests are generally more accurate and are used to confirm positive results from a rapid test. As your lab tests were negative it sounds like you do not have HIV. You should have this discussion with you clinic or test lab though.
samzo • 4 December 2011 1:21 pm
can a cold and flu tablet cause a prick test to be positive when the tablet are taken for a week, i read that flu tablets and vaccine cause different hiv test to yield a positive result.
Simon Collins • 4 December 2011 1:30 pm
Information about testing is on this FAQ page.
http://i-base.info/qa/faq/hiv-transmission-and-testing
Babou • 5 December 2011 10:15 pm
Hello, am a male of 22 years of age, i had a single episode of unprotected sex with a lady i believed to be HIV positive … i went for testing after 10 weeks, it came out negative .. and at 94 days it came out negative too…
Simon Collins • 5 December 2011 10:30 pm
Information about testing is on this FAQ page.
http://i-base.info/qa/faq/hiv-transmission-and-testing
Sam • 6 December 2011 4:55 am
Hi, I had sex with a condom on 27th oct 2011, with a female who I knew earlier but v met after 4 years…I got a tridot test done which was negative at 4th week, later I got sore muscle etc. IS Tridot test is accurate at 4 weeks ? are this symptoms of Hiv? I am planning to take another test tomorrow but very worried plz suggest??
Simon Collins • 6 December 2011 5:00 am
Information about testing is on this FAQ page.
http://i-base.info/qa/faq/hiv-transmission-and-testing
rohan • 6 December 2011 2:54 pm
Hi i had sex on july after that i saw some blood on my condom and my hand on september i have joint pain and mild fever after 3 month i check hiv rapid blood test twice the result came negative and i test again after 4 month also the result came negative still i have some pain on my joint so am worried this rapid test is accurate or shall i test again some other test ex elisa pls reply me
Simon Collins • 6 December 2011 3:00 pm
The information on the FAQ page says why a test a three months does not need to be repeated.
http://i-base.info/qa/faq/hiv-transmission-and-testing
Adr • 7 December 2011 7:59 am
Hello. I had unprotected sex with a girl of unknown status 11 weeks ago. Since then I have had the following tests: HIV ECLIA Antibodies at 3, 5, 8, 10 weeks; HIV COMBO (Antigen and Antibodies) at 6.5 and 9 weeks; HIV PCR RNA (Viral load) at 3 and 5.5 weeks and HIV PCR DNA (proviral DNA detection) at 7.5 weeks. My tests were negative. Could I still be infected? Do I need to retest at 6 months? Please help, I’m very scared because I keep getting recurring aphtous mouth ulcers and i have a white tongue. Please help.
Simon Collins • 7 December 2011 8:00 am
You are very unlikely to be positive with a negative result at 10 weeks. In the UK this needs to be confirmed at 12 weeks, but not 6 months.
payman • 8 December 2011 6:40 pm
hi simom i know sombody hij was after 3 year after onprotect sex hij test after 3 year positif is this posibel .
Simon Collins • 8 December 2011 7:37 pm
No. There are likely to have been more recent risks or a fault with the earlier test. I have never heard of cases where somebody has taken three years to develop HIV antibodies.
alien • 12 December 2011 3:56 pm
Dear simon , thanks for your highly efford .
As you mentioned I read the link you attached in your previous reply , I did have my test today after 40 days and it came back negative ! My test was hiv 1 &2 antibodies single assay , when I asked them about the kind of test , they said elisa .
My questions is , does 40 days mean 95 % is accurate !?
I hope I have a reply on my question , bez I read a lot of staff in the internet and I’m so confused ! Every single time we make sure that’s we r fine , we have other websites says , there are no antibodies in the first 4 weeks at all to be produced by body .
I’m srry for disturbing simon , and I really appricate your reply .
geronimo • 13 December 2011 4:23 am
Hi
I had an exposure where pre-ejaculatory fluid got in and around my anus, got a pcr rna test after 1 week, negative finger prick at 4 weeks, and negative antibody blood drawn test at 7 weeks. going in again soon but I need to know if I can relax a bit. Thank you so much and thanks for producing this great information to all of these people.
raj • 13 December 2011 4:56 pm
Sir , I received oral sex in europe 3 years back..but i m not well from past 3 months..night sweats ,fatigue , weakness, evening uneasiness and mild rise in temperature, alteration in bowels ,lost 7 kg in first one month of illness. My elisa (ECLIA , MEIA) , western blot and dna pcr qualitative tested in india . All are negative . but my worry is ..weather these test done in india detect the subtype found in europe.are these symptoms due to hiv ? My cd4 counts is 1129.
Simon Collins • 13 December 2011 5:00 pm
Please see this new guide to HIV testing and the risk of sexual transmission:
http://i-base.info/home/new-i-base-guide-hiv-testing-and-risks-of-sexual-transmission/
This resource has been developed in response to the many questions i-Base get on testing and transmission.
It explains whether you need to test and how to interpret test results.
This discussion thread will not take further posts.
Questions about HIV treatment can be asked at this link.
Simon Collins • 13 December 2011 5:00 pm
See the testing FAQ.
db singh • 14 December 2011 8:13 pm
exposure after 3 days we tested for hiv, and result found negative, and i did second test for hiv, after 96 days again it found negative i am safe from hiv…?
bejamin • 15 December 2011 4:39 am
Hi doctor, am from Nigeria and all I can say is that this forunm is really helping many people. I had an encounter with one girl and after 3months and 10days later, I remembered giving her oral sex and aslo fingering her during this period, right now is 17weeks and I am going for another test and I hope it will come out negative,I took her for the hiv test in the 16th week and she was negative,It came bak negative!n am scared as hell because I gave her oral sex,, later I also had sex with another random lady that I jjust gave a lift inb my car on october 26 and now it is 7th week,am planning to go for a test when it is the 8th week, am so scared because on the 7thweek I developed a flaky skin on my neck, I don’t knw may be its because of down here in Nigeria, we are experiencing harmattan and I used a hot water to bath,I don’t knw if by accidentally it affected me.I also did a viral load test in the 6thweek confirmed with a westernblot test and it was negative.pls am dying slowly due to anxiety ,pls help me.
bejamin • 15 December 2011 4:42 am
And I forgot to vtell u that during that period I had serious headaches, and now I just developed headache, I took a typhoid drug and the headche is gone, and also I hav e been stooling for sometime consistently.dunno wat to think anymore. Is 8th week antibody test safe
Nanda ctr • 15 December 2011 11:20 am
can tell any one normally window period is at least 4–6 weeks after the exposure ( i.e completing the 4 = 28 days r entring to 4 weeks 21 days) y becoz i have tested Tri-dot test exactly 26th day it was negative have i test again r stll have to v8 up 2 3months plz help me
alien • 15 December 2011 2:03 pm
I did one more test today with new modern system , they said it detect enzeme and antibodies , which give a really accure results . I just took my result and it was negative less than ,11 .
I talked with the supervision in that lab , she said its so accure ! But if you still or adopt that u r infected , you can retest after 1 mounth just to calm you down .
Btw my test today is after 45 days .
Cross fingers guys , I wish all the best of luck guys
Matt • 16 December 2011 1:18 am
Hi. I had unprotected sex a month ago. I also had unprotected sex 4-5 times before in my life. I did a test called :ANTI-HIV p24/Ab1/2/0 yesterday and it came out negative. The doctor said that the test is accurate. Should i do another one?
MIMI • 16 December 2011 12:03 pm
Hi simon,
I did HIV 1&2 Ab-Ag (ELCIA) 3 Weeks post exposure (Non Reactive)
HIV p24antigen 4 weeks post exposure (Non Reactive)
HIV 1 & 2 Ab-Ag (EIA) 5weeks post exposure (Non Reactive)
Hepatitis C (EIA) 5weeks post exposure (Non Reactive)
VDRL 5weeks post exposure (Non Reactive)
1)Am i Hiv Negative? Do i need to re test? my Dr told me i did not need to re test.
2)what is combo test? combo test also use menthod (ECLIA and EIA)? or Menthod ECLIA and EIA only look for antibody not for antigen?
3)5 weeks post exposure HEP C and VDRL and HIV NEGATiVE,if i re test at 12week is it my result will come out POSITiVE? sorry my bad english
Simon Collins • 16 December 2011 12:12 pm
See the testing FAQ. Your questions about testing are answered there.
Simon Collins • 16 December 2011 1:30 pm
See the testing FAQ. The information about the timing of the testing will answer your question.
Srini • 17 December 2011 6:24 am
HI,
I have done Oral sex in the month of July or First week of August. I done HIV PCR & ELISA & AB/AG test in the month of Nov 2011 all the test are negative.
I want to know that is there any chance that HIV virus is present in my body?
Simon Collins • 17 December 2011 6:26 am
See the testing FAQ. Three months is ok.
Ocean • 17 December 2011 3:20 pm
I was exposed to HIV via sexual contact. I took a OraQuick rapid oral fluid test post 14 weeks is my negative test results conclusive since I was tested with a 2nd generation rapid oral fluid test? I had all the ARS symptoms, but no fever or swollen lymph nodes.
Do I need to test with a 3rd / 4th generation blood test?
Simon Collins • 17 December 2011 3:30 pm
See the testing FAQ. 3 months is fine.
alien • 19 December 2011 3:02 pm
Srry simon , I forget to ask you there is two test I’m done with , first one said none – reactive ,11 less than ,25 and the other one is ,6 less than 1
What is the diffrent between these two numbers !?
Simon Collins • 20 December 2011 11:21 am
See the testing FAQ page to explain the numbers.
Ken • 21 December 2011 7:15 pm
on a drunken night a girl in italy performed oral sex on me as well as very short vaginal and anal sex. This is the first time i’ve ever done anything like this. I took a test about two months later it was negative. Then i took a rapid test a few days shy of 3 months and i came up positive on 2 rapids and negative on another then negative on a western blot and was also told negative for all STD’s and was told I had a genital wart which was burned off. So i got another western blot test done 3 days shy of 4 months and it came up negative. I am almost affraid to go back again for another test because i hear it can take up to 6 months. Do you think im in the clear and just being a hypercondriac or what?
Simon Collins • 21 December 2011 7:30 pm
The negative tests at three and four months would be interpreted in the UK as you not being HIV positive.
Please see the new i-Base guide to HIV testing and the risk of sexual transmission.
Sally • 22 December 2011 12:07 am
I tested negative with a finger-stick rapid test at 2 and a half months, but have been having ongoing Acute seroconversion symptoms and probable thrush, so they did a pcr/viral load test. Today I was told there was no virus detected, and that this confirms I do not have hiv. However, your site indicates this should not be used as a confirming test. My husband is mad because I don’t entirely trust the viral load test.
Simon Collins • 22 December 2011 12:30 am
The viral load test shows that the symptoms are unrelated to HIV. It is not being used to diagnose HIV but to help eliminate the possibility that HIV is causing the symptoms. If these were seroconversion symptoms, then, by definition, there would be detectable virus. This test was being use to reassure you, as otherwise you need to wait until 3 months for a confirmed negative antibody test, which, technically, you still need to do.
Please see the new i-Base guide to HIV testing and the risk of sexual transmission where this is explained in more detail.
juci • 23 December 2011 6:28 pm
Hi. I’m a 23 years old male. I had unprotected sex everyday with a friend between 24th sepptember 2011 and 21st october 2011. We had issues on 21st october and she angrily claimed to have infected me with HIV. I had a little cut on my left hand the last day I saw her. ( Now I dunno if the infection might have been from sex or the cut on my hand) I don’t know her hiv status. On the 25th I stated feeling funny and by 28th I developed a sorethroat and fever which have both been persistent. Then the head aches started. Unexplained weight loss, heat rashes, swollen lymph in my neck, red spots on my arms. My tongue recently turned whitish. I did tests at 2weeks, 4 weeks and 6 weeks and they all tuned out negative. I did a rapid test at 7 weeks and. It also turned out negative. I did a viral load test at 6 weeks and it tunred out negative (undetectable). These symptops don’t seem to go away and its been 13 weeks since I first had sex with her and 9 weeks since I stopped. And I’ve had all these symptoms for 9 weeks now. I’m very worried even though the doctor said there is no hiv in my blood from the viral load test. Do I still have reason to worry? He said the symptoms will fade away and I shouldn’t worry. He says my head is magnifying things. He said I should only return for another test after another 12 weeks. I’m very scared. I’m really praying its not HIV but then can my anxiety be causing all these symptoms or something else?
Simon Collins • 23 December 2011 6:30 pm
Please see this new guide to HIV testing and the risk of sexual transmission:
http://i-base.info/home/new-i-base-guide-hiv-testing-and-risks-of-sexual-transmission/
This resource has been developed in response to the many questions i-Base get on testing and transmission.
It explains whether you need to test and how to interpret test results.
This discussion thread is now closed.
New questions about HIV treatment can still be asked at this link.