[Question #481] global disparity between performance of antigen/antibody tests?

40 months ago
Hi again Doctors,

I have returned again seeking some information after difficulty accepting my 6 week negative antigen/antibody test as conclusive. 
I know you both have a steadfast view that an antigen/antibody test done any time after 4 weeks post exposure is conclusive...and how I would love to believe this. However, I have read online that some tests are more sensitive than others. 

Given I am in Australia, the antigen/antibody test I took is probably a different manufacturer to your well known USA based manufacturers such as Roche, Abbott, Vidas etc. Given we don't know the manufacturer, is it safer to assume the test was NOT indeed conclusive at 4 weeks. The laboratory who did my test states the window period is 3 months..do you think they state this knowing their test is not sensitive enough at 4 weeks?

I know I'm really splitting hairs here...but I believe it is a valid question. Surely the tests are not all equally effective worldwide? Dr Sean Cummings states he cannot comment on other antigen/antibody test conclusiveness (under 3 months) other than the Vidas duo...leaving me to believe different test brands perform differently. 

Do you have any experience or knowledge of this?

Thank you for all your time  


Edward W. Hook M.D.
Edward W. Hook M.D.
40 months ago

You are splitting hairs.  You asked for our input and have received it.  You seem to prefer other information you have gotten over the internet.  That too is your right.  We are not going to engage in a debate based on things that you have heard on the internet. 

The HIV epidemic is a global epidemic.  Each nation has its own standards for what is permited to be licensed for sale however the market for HIV test is a GLOBAL market and manufacturers seek approval by regulatory bodies such as the FDA in the US and WHO on a global scale.  Likewise I am confident that standards for licensure in Australia are quite similar and effectively equal to those of other developed nations.  Typically all licensed tests are held to the SAME standard for approval and any differences in test performance tend to be miniscule and not clinically meaningful, more often reflecting differences in study methods than meaningful differences in test performance.  If you choose to distrust them that is your right and, in my opinion, problem.  Globally the data indicate that approved antigen/antibody tests provide definitive/conclusive test results 4 weeks after an exposure. 

Nothing more to say. I wish you well.  EWH

---
40 months ago
Thank you for your response Dr Hook. I am aware I am splitting hairs but that 'official' 3 month window is very hard to disregard. I very much so hope that Australia is using tests just as sensitive and effective as those you are familiar with in the states. I just have a couple more questions to wrap up..

1) Would you say ALL people would have detectable antigen or antibodies by 28 days (except those who have taken Pep?)

2) Do you think long term SSRI anti-depressant use (I've been on them for 8 years) could cause immunosupression? I know long term use is associated with such problems as reduced kidney function. 

Thanks again
Edward W. Hook M.D.
Edward W. Hook M.D.
40 months ago

Sigh, you just keep asking the same question.  Einstein said that one definition of insanity is to ask the same question again and again and expect different answers.  My responses are NOT going to change:

1. YES!

2. No, SSRIs do not cause immunosuppression.  The fact that you are taking SSRIs however does suggest that you have a mental health professional whom you interact with.  I suggest that, for your own good, you discuss the basis for your persistent, unwarranted anxiety and inability to accept that your test results, performed in a professional and, I presume, licensed setting, are valid and that you did not get HIV form your exposures of concern.  It cannot be good for you to be spending so much time repeating the same questions again and again.  EWH

---
40 months ago
Hi again Dr Hook,
Thanks for bearing with me.

Yes, my tests were completed in a professional and licensed setting in Australia, but being inside the 'official' 3 month window is very daunting -  especially when the pathologist slip so boldly states 'testing under 3 months does NOT exclude HIV infection'. Hence why many of us anxious folks turn to the internet to console/inflame our fears in the interim.

For my final question I will ask...in the last 2 weeks I have experienced a greater incidence of mouth ulcers (mostly on the insides of my cheeks). Some are painful, some not. Some are small and pimple like, whilst others are more like a blister. It is nearly 8 weeks past my last exposure (but my more high risk exposure was 12 weeks ago). My last negative test was at 6 weeks past last exposure. 

I have read your previous posts on medhelp that say mouth ulcers or canker sores are usually only symptomatic of HIV in the later stages of infection. Would you still concur with this? Or should I be concerned with the sudden onset of these after my exposures. 

Thanks again Doctor.



Edward W. Hook M.D.
Edward W. Hook M.D.
40 months ago
Correct, asking me to repeat the answer to this question, like your others will  not change the answer.  Mouth ulcers and canker sores are not a sign of recently acquired HIV infection.  They are however a sign of anxiety.  This will complete this thread.  EWH
---