I have been volunteering in a shelter for battered women for awhile now and sometimes I feel like some of the information being given out is confusing me and I am not sure if I am ever asked how best to answer the question.  One thing I have heard a couple of times now that if someone with HIV is on medicine and their viral load becomes undetectable they will test negative, yet when they get tested for for HIV antibodies the screening test that is done they are always positive.  I did some research and I just wanted to see if this statement is accurate:  Once you get HIV you will always test positive for HIV antibodies for life, but on medicine you can get tested for viral load (a different test) and that can become undetectable.  So when we tell people in this situation that they are negative it means their viral load is negative so it is unlikely they can transmit the disease - but they will always test positive for HIV antibodies.  Is this correct?  Does this also apply to other antibodies like HCV and HBV - with HBV the core antibody does that also stay positive for life.  Thanks a lot for creating safe spaces for people to ask questons like this, I just want to make sure I understand this, I know I probably will never be asked this because its not my job when I volunteer - but I heard conflicting things and when I did my research this is what I found and I just want to make sure I am up to speed.  Thanks in advance. 

sorry made an error in a statement I wanted you to validate for me - HBV core antibodies remain for life, but HCV may or may not last for life, but do last a long time.  My main question is below about HIV antibodies.  Thank you so much Dr.

Welcome. Thank you for your kind words about the forum, and for a thoughtful question. And thank you for your important volunteer work.---
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yes this did help - thank you, I asked for my own knowledge bc I heard somebody say they were functionally cured on an intake form and I didn't know what that meant and was to embarrassed to ask the staff bc of looking like an idiot, so I read about myself because I was curious.  Thank you for the great answer below, I understand things better now.  Thanks for what you do Dr. reading through all the forum responses, its clear you help a great deal of people here and I looked you up and saw how distinguished you are, you have had a wonderful career and should be really proud of what you have done with your life.

Hep B is the most confusing one - the HBsAG is the antigen right (that can be either positive or negative depending on status) and the antibodies HBsAB and HBcAB are the antibodies and these are the ones that stay positive for life correct?

Thanks for the thanks. I'm glad to have helped.---
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last question so HbsAB is the antibody marker of immunity & HBcAB is the marker that an infection occured at some point, so if you were ever exposed to hep b whether you recover or not HBcAB will always be positive, so if the HbsAG is negative from what you said below, the HBcAB would still be positive right, but this person is not infectious, also does the HBcAB then stay for life or decades and decades it can still be detected?  I think I read about isolated HBcAB and I think that is what you are refering to - this is also rare correct?  Thanks a lot for your time, I'm very inqusitive and just wanted to make sure I understood all this because its very confusing - so is what I wrote above correct?  Thanks again Dr, I know you only allow three replies so this will be my last question.

By "exposure" I think you mean infection; exposure (without being infected) doesn't produce a positive result for any HBV marker (or any other infection). If HBcAb is positive, it means someone is or has been infected with HBV, and once positive remains positive for life. With negative HBsAg, that person is not infective and usually no longer has active infection. That said, it would be very rare to have only HBcAb; previously and currently infected persons also are positive for HBsAb.---