HIV 1/ 2ag /ab combo test

Originally Posted: 
Saturday, March 16, 2013
Question: 

 

hi

i have a question . i got HIV ag/ ab combo screen test done ? what kind of test is that? does that look for anti bodies?

the results said : non reactive, HIV final interpretation: no HIV p24 antigen and no HIV 1/HIV 2 antibodies detected?

also another question

i got another HIV test done which was after 2 years of possible exposure and i am still worried i thought i will feel better after getting done after two years. this test was HIV1/2 AG / AB COMBO SCREEN. and it was non reactive and said no HIV p24 antigen and no HIV1/ HIV 2 antibodies detected. whats the difference between those two type of tests i mentioned ? and how accurate are they? do i need to retest again? two years is more than enough to know your status right?

and also i had a rapid test done as well and it was non reactive. what kind of test is a rapid test and how accurate is that?

please if you could answer me . i will wait for your reply. thank you.

and also even though  you guys are not doctors or anything but the information you guys provide are accurate right?

i appreciate all your help . thank you . have a nice day

 

Answer: 

 

Hello and thank you for using the AIDS Vancouver helpline as source for your HIV related information. I will do my best to address your questions.

AN HIV ag and ab Combo or Duo test will look for HIV Antigens and HIV Antibodies. You can trust in these results as this 4th generation EIA test is one of the most accurate on the market (99.9%). This Combo test first looks for P24 antigens immediately after infection and only for the first 2 to 3 weeks. The second part of this test looks for antibodies and has a window period of between 4-12 weeks. Most HIV specialist will consider this test conclusive at 6 weeks.

 HIV 1 is the most common form of HIV, while HIV 2 is a strain of the Virus usually found in Sub-Sahara Africa. You are correct after 2 years no further testing is required.

A Rapid or "point of Care" test also has a window period of between 4 weeks and 12 weeks with an accuracy rate of 99.6%. In Canada the Rapid test is administered by doing a finger prick and testing the blood immediately after. In the United states they use blood or oral swabs for their rapid tests.

While we are not doctors, we are trained in giving the most up to date and reliable information in regards to HIV. We at the Helpline get our information from three sources, the World Health Organization (WHO), the British Columbia Centre for Excellence (BCCfE) and the Canadian AIDS Treatment and Information Exchange (CATIE).

I am hopeful that this information gives you some clarity in the testing process. Please do not hesitate to contact us at the Helpline again, should you have any follow up questions.

Yours sincerely,

David

AIDS Vancouver Helpline

helpline@aidsvancouver.org

604 696 4666

Comments

Submitted by Flavius (not verified) on

Hello,

I had an RNA quantitave test at 23 days and a Duo test( Ab/Ag) test at 32 days. Both came back negative.
My question is, what is the likelyhood, that I would still test positive after three month, considering the combined results of the above tests.

Submitted by davidn on

Hello and thanks for the questions. While having had 2 HIV negative test at 32 days is a great indication that you have not been exposed to HIV, an HIV is not conclusive until 12 weeks post risk exposure.

it should be noted that many HIV specialists will consider the 4th Generation Combo test conclusive at 6 weeks however the International Guidelines still indicate an HIV test is conclusive at 12 weeks.

All the best and we are here if you have any other questions,

David.

 

Submitted by joseph (not verified) on

If anigens disappear in 4weeks and antibodies are not produced by that time how accurate will the test be

Submitted by davidn on

While antigens will not be read after the formation of HIV antibodies, some people will take up to 12 weeks for these HIV antibodies to form to detectable levels that can be read from a test.

All people living with HIV will have developed detectable HIV antibodies in 12 weeks or 84 days. This is considered the conclusive time for an accurate HIV test.

All teh best,

David.

Submitted by joseph (not verified) on

Is 6 weeks ab/ag combo test consider conclusive or need to re test at 12 weeks and what are the chances of a positive result at 12 weeks?

Submitted by davidn on

Hello some HIV specialist will consider a 4th generation Combo test conclusive in just 6 weeks, official International Guidelines still indicate that an HIV test is not conclusive until 12 weeks, post risk exposure.

While we at the Helpline cannot speak in terms of chance, we do believe that this 6 week negative is a great indication that you are going to continue to test HIV negative.

All the best,

David.

Submitted by Flavius (not verified) on

David,
You must have misread my question!
I did not have two HIV tests at 32 days. I had a RNA quantitatve test at 23 days, which according to most experts is 99 % accurate at after 3 weeks, since it looks directly for the virus itself and therefore does not depend on the immune response of the individual as manifested through the production of anti body.Viral replication is differrent from case to case yes, but RNA tests have a windown period of 1 to two weeks,not 4 to 6 weeks as anitbodies because after all the virus cannot "hide" or "sleep" in the body, either it is there and it replicates, or it does not.
If the virus is there, and after the initial few days of infection it will replicate very fast so that it would be very very difficult to miss( Only human error could explain a miss) after 2 weeks.

On the other hand, yes, Duo tests are not a 100% conclusive at 12 weeks, although UK authorities consider them very reliable at 4 weeks, that is to say, they will diagnose most people.

Now my question again:

Considering my negative RNA Quantitave test at 23 days, and my negative and a Duo test( Ab/Ag) test at 32 days, is there really any chance that I would still test positive after 12 weeks? I know what the guidlines say, they normally refer to antibody testing though not to RNA Quantitative for the reasons I explained above.If you do not know the answer to my question, I will also accept that, but please do not quite the guidlines, that really doesn not help someone im my position.

Thank you for your precise answer

Submitted by davidn on

Hello, at 32 days you have indicated that you have had two HIV tests, one (RNA) test at 23 days and another (Ab/Ag) at 32 days. this indicates that at 32 days you have indeed had 2 HIV tests in 32 days. My mistake if I have not understood the information you have provided.

While quoting guidelines may not be of benefit to you, i cannot respond to ""chance"" questions. It is now up to you if you wish to have any further testing done. However based on the information you have provided, this is a great indication that you will continue to test HIV negative.

An HIV Duo 4th Generation test is conclusive at 12 weeks., and many HIV specialist will consider this 4th Generation test conclusive at just 12 weeks.

Again i am sorry i cannot give you more of a precise answer to your chance question, however we do encourage you to speak directly with your doctor and or the lab where you had testing done, and it is hoped they can provide you with the answers you are looking for.

David.

 

Submitted by joseph (not verified) on

Have been exposed to hiv unprotected sex I took ag/ab combo test result negative at 6 weeks
However I have developed body aches and pain under my armpit. Could this be a symptom of my body fighting virus and
Armpit pain lymph node swollen even though I can't feel it? Its been on and off for about a month now.

Submitted by davidn on

Hi and thanks for the question. Some HIV specialist will consider an HIV ""combo"" test to be conclusive at just 6 weeks, however the International Guidelines still state that an HIV test is not conclusive until 12 weeks, post risk exposure. We at the Helpline recommend you have a final HIV test done then and we are hopeful that you will indeed continue to test HIV negative.

Pain and swollen lymph nodes are in no way an indication of HIV and only testing can tell you this information. If this pain continues or worsens, please seek medical attention.

David.


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