p24Ag test similarities and differences

[luddite]

Background:A friend in Germany was diagnosed with UC and HIV in 2009 when he was very ill.I believe that he is not pos.,based on the info he gave me on symptoms of his illness and the questionable test results due to having a poss. autoimmune disease as well as being over-vaccinated for 14yrs by the military.I insisted he be retested after I put him on a high-fiber diet (only) and took him off Atripla.After not taking Atripla for approx. 3mths his VL went down by 300,which has confused his "doctor".MY QUESTION: What are the similarities/differences between Anti-HIV1,0.2+p24-Ag Abbott,4.Genaratio(pos. result) and HIV-p24-Antigen Murex HIV Antigenmab(neg. result)?I could only find from my own research that p24Ag is tested in both,that the tests are from 2 diff. companies,that the Murex is more sensitive,and that the Abbott is for 4th generation.

[luddite]

Thank you for your response.While waiting for your reply,I found out that the Murex test involves a monoclonal Ab(MAb not mab) which is a highly specific Ab produced by a lab. grown cell clone either of a hybridoma or a virus-transformed lymphocyte.A 4th generation test simply tests for Ab and p24 Ag,has a high sensitivity and a high rate of FP.It's all about specificity vs. sensitivity.And,yes,it would be nice for my friend to get all his lab results when he requests them.But when Atripla cost about $1500/mth,and you have stock in pharmaceuticals...However,I have found out that Germany has a few pt's rights and one is the right to med. records.Minus Dr.'s notes.I am not a denialist,but you don't know the entire story.And there are approx. 60 factors that cause FP in Elisa/WB,and vbiral load testing is not specific to HIV.VL tests don't even have the ability to isolate or measure actual viruses.A VL is also affected by viral,bacterial,and parasitic infections as well as sepsis....Thanks again for trying-luddite

[Dr. Jose Gonzalez-Garcia, MD, MRCGP, PhD]

Hello,
Thank you very much for your contribution to our HIV forum.
I am not familiar with the Murex test, but as far as I understand, they are both very similar, detecting for both, HIV1 and HIV2 antibodies, as well as the p24 antigen.  In any case, I think this seems to be now irrelevant for your friend.  If he has a detectable viral load, there is no question about the fact that he is HIV positive, regardless of his underlying medical history.  Viral loads can fluctuate due to many different factors and it is possible that his immune system is responsible for that viral load drop, even after having stopped the anti-retroviral medication.  it is important that he continues monitoring this, as well as his CD4/CD8 count on a regular basis.
Best wishes,
Dr José