ABOUT HIV WINDOW PERIOD

[HCW]

A few weeks ago I post a question about a probably exposure to blood from a HIV infected patient ( Superficial cut  on the hand using gloves ). Your response was very clear and alleviate my anxiety. I  am agree with you that the new EIA assay can reduce dramatically the window period. The problem is that usually in USA the Labs don’t  use the third generation test, and the CDC knows it, is that the reason for its official 6 months window period and the 97% of seroconversion at 3 months. I was tested with Labcorp And I was surprised when found that they use first generation assay  (This test uses a viral lysate as the antigen source and detects antibodies by specific immune binding and subsequent color development (enzyme immunoassay (EIA) technology).
Check Labcorp webite:  http://www.labcorp.com/datasets/labcorp/html/chapter/mono/se028900.htm

The third generation use the follow Methodology:  ELISA III technology is the antigen sandwich method in which an enzyme (alkaline phosphatase or horseradish peroxidase) is conjugated to an HIV antigen (similar to the immobilized antigen on the solid phase). The antibody in the sample is "sandwiched" between two antigen molecules, one immobilized on the solid phase and one containing the enzyme.

So I think that in USA the window period is 6 months because the old test.
I did an extensive search and almost all the other countries around the world use a 3 months window period but they use third generation assay, is a public health law.
If you check in the officials health web sites of countries like Australia, UK, France, Germany, Sweden, Spain, New Zealand, Switzerland, South Africa, Chile, Argentina, Colombia, Mexico, Brazil, Denmark, Norway, Finland, China, etc. All this countries are using the third generation test and 3 months window period. Even some of this countries check always for HIV 1, 2 and Group O. ( Routine )
But in USA I don’t know why we are using the old test, maybe for occult economics or business reasons.
I was tested at 4,7 and 12 weeks (Negative) with the Labcorp EIA (first generation), I know that with a third generation is enough but that is not my case and maybe everybody here have the same situation.  What is your opinion?
Thank you for your time
Interesting info:
http://www.phppo.cdc.gov/dls/ila/cd/cambodia0704/day1/3-UpdateOnHivTesting.ppt

http://www.faetc.org/PowerPoint/AAHIVM-Nov-1-2003/02-Kurtyka-HIV-Testing-and-Superinfection-11-01-03.ppt

http://www.aidsportugal.com/article.php?sid=980

http://www.phppo.cdc.gov/mlp/pdf/labhiv/MBusch.pdf

[H. Hunter Handsfield, M.D.]

I am not an expert in HIV testing technology, but I'm pretty sure you are wrong about first vs later generation tests; virtually all labs use the most modern technology and you can rely on negative results at 4-6 weeks.  (The end of your first paragraph implies you may think that all ELISAs are first generation.  Not so; I believe the newer tests are ELISAs as well.)  I suspect you either were misinformed by LabCorps (perhaps spoke with someone who doesn't know the evolution in test technology), they misunderstood the question, or you didn't ask it clearly.

Anyway, my opinion is that you can be 100% sure you did not acquire HIV if your test is negative 12 weeks after exposure; and that almost no labs in the US are using any but the most up-to-date HIV testing technology.

HHH, MD

[joeworried]

I will let others more knowledgeable than I respond to your comments.  But I find your assertions absolutely incredible.  If LabCorp were used dated technology to perform such a vital test, they would have been sued out of existence long ago.  I looked through the websites you identified, and found nothing new or that supports your assertions.

[HCW]

Well I dont want to worrie you, I know the anxiety that all this produce, this 12 weeks has been the worse scary days in my life. Check the different techniques ( ELISA I, II AND III) Compare it, and check the Labcorp assay.

[psyber]

I recall the doctor said in this forum that the new test can detect the HIV antibody about 5 days earlier than the old one during the first 6 week period. The sensitivy between the new test and the old one are almost the same at 12 weeks and beyond. I dont remember exact thread, but it is very close to what he said. Please correct me if I am wrong.

[HCW]

The difference after 12 weeks with the older and new test if no too much I am agree but in the firts weeks is notorius, even after 12 weeks is some difference around 3%
Check this journal

http://www.aidsonline.com/pt/re/aids/fulltext.00002030-200010200-00014.htm;jsessionid=DUANX2Yg1NjNADh7fDphQTJEGsJSkP13lgxGBDrOIUM0yn1Tckfx!-1932480194!-949856144!9001!-1

[henry2]

It is "almost" true.  LabCorp uses a second generation anti-body test.  I have verified this information twice through the internet site that I used for testing.  They even called LabCorp to make sure.  I got a DNA PCR test at 28 and 51 days, both negative, so hopefully that is proof I am truly negative.  At the 51 day mark I also got an anti-body test, but since it was second generation, it was probably useless.

[psyber]

That journal was published in Oct. 2000. The data was collected in 1987.

I called my lab today. They could not tell me what generation of the test they are using. The only thing they know for sure that it is an ELISA enzyme liked essay test. They said they consider their procedure are gold standard. I dont blame them for not knowing. They are chemists not doctors. They told me that they test for both HIV1-HIV2 by default. This made me feel that they are very up to date with this issue. I have the Doctor in this forum and Dr. Bob at theBody.com who are HIV experts. They said 12 week is conclusive. This is enough for me to believe in my 12 week result. I am HIV negative.

[joeworried]

I believe you are correct in noting that there is not a great difference in the window periods associated with the various generations of HIV tests (on the order of a week or so).  The reason for this is that once seroconversion takes place, antibodies build up very rapidly (exponentially).  JohnnyV referenced a paper several weeks ago that talked about ARS and had a very nice graph on the buildup of the virus and antibodies in the first two months following exposure.  

Most other websites indicate that a negative HIV test at 12 weeks is conclusive regardless of vintage.  You are obviously HIV negative.

[jamespeter11]

Can anyone tell me what is this test, is this test is standard ELISA test.

"we are using the latest automated CMIA (chemiluminescent microparticle immunoassay) technology for our Anti-HIV 1&2 screening. This ARC HIV Ag/Ab Combo assay will have better sensitivity and specificity for the simultaneous qualitative detection of HIV p24 antigen and antibodies to HIV type 1 (Group M & Group O) and/or HIV type 2, if comparing to other screening methods like the manual ELISA 3rd generation etc"

Is this test is standard ELISA test

[benzy]

hi i hope me question can be answered as soon as possible. i had protected sex but my hands had touched her viginal fluid although i wiped it dry also touched the inner lining of the condom.i went for an anti-body test 5weeks later which was negetive, i was instructed to come back after 3 months for a re-test. please can i rely on the first negetive test? and what are the chances of being infected if she is positive. pleasse help me.. if possible mail a copy of your answer me. thanks!!

[mattwisconsin]

The 5 week test they say is about 90% definitive.  By week 6 or 7 it reaches an accuracy of 99% or greater.  Settle down just a little, you will be allright!  You had an almost 0 chance of ever contracting any STD.

[oil]

Hi, i just want to ask if the rapid tests are elisa ? does anybody know about Mirates Hiv home kit from the netherlands?

How accurate after 5 weeks and a half, please?

[oil]

Hi, i just want to ask if the rapid tests are elisa ? and if so what generation of elisa is used, please does anybody know about Mirates Hiv home kit from the netherlands?

How accurate after 5 weeks and a half, please?

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