Test generation

[scaredhiv16]

Hi,
I have been reading this (and other) forums and I could not figure out one issue. I'd like to be tested for HIV, but I am waiting the window period. Most experts say that modern HIV tests are much more sensitive than the previous ones, that is why the window period would be shorter nowadays. However, oraquick (only as a example) is perhaps one the most common test in US (free cost - I don't have health insurance). But as far as I know it is only 2nd generation. In other words, it works like the older ones. Then, why do many experts think the window period is shorter nowadays?

[Edward W Hook, MD]

I think you understanding of the window period may be incorrect.   As tests for HIV have been produced over time their performance has evolved.  There is no question about this and the fact is that I know of no expert who has seen a person seroconvert in more than 8 weeks unless the person was in an unusual situation such as taking anti-HIV medications to prevent infection.  

Referring to "generations" plays into person's paranoia about window periods and timing of tests which are fed by internet-fed fears of the window period contributing to negative tests and overly conservative estimates of test performance by the manufacturers and governmental agencies, both of whom feel they have much to lose if they are later found to be incorrect.    You don't mention how long it has been since your exposure of concern so I can't comment on your situation.  If you are interested in optimal and free testing, go to your local health department and get tested. It should not cost you much, if anything and there is a fair chance they will be using highly advanced testing procedures which detect infection very early in the course of infection. EWH

[scaredhiv16]

No need to apologize. Thanks for helping.

[Edward W Hook, MD]

I apologize.  I just saw my typo.  Antibiotic do NOT interfer in any way with etection of HIV.  I was typing too fast.  Again, ANTIBIOTICS DO NOT INTERFER IN ANY WAY WITH HIV TESTING.  So sorry. EWH

[scaredhiv16]

But you have said that antibiotics do interfere. And I really read in a study that antibiotics lower RNA HIV level. Why do people don’t warn us before getting test? In the test, we are always told that it does not interfere (they don't even ask us about the name of the antibiotics).

[Edward W Hook, MD]

Azithromycin has no effect at all on HIV tests, in any direction.  Believe your test result.  EWH

[scaredhiv16]

I am a bit worried then. When I did my last test I had taken azithromycin 1g (single dose) 3 days before. It was negative. The counseler had told me it would make no difference. Does it mean it could have been a false negative? Or it interfers only to be a false positive?

[Edward W Hook, MD]

Antibiotics do interfer.   I think the health department is being too conservative.  The recommendations for testing at 3 and even 6 months are the result of two factors- data from older tests no longer used (you really do not need to worry about which generation of tests you were tested with, at this time virtually all tests are far more sensitive that they were even 2-3 years ago when the 3 month recommendation was made) and secondly, the fact that some, mostly governmental agencies which have to provide recommendations for virtually everyone without the sort of interactions such as those you get with your doctor or on personalized sites such as this one, feel the cannot "afford" to be wrong and therefore make recommendations and guidelines which leave most people unnecessarily nervous for 4-6 weeks longer than the 6-8 weeks it takes virtually everyone to develop HIV antibodies.  

While I know nothing about your exposure it would be most unusual if your test results were to change over the next 3 weeks. In fact you would be the first such person to be in this situation is over 3-4 years.  EWH

[scaredhiv16]

I have already been to the public health center. They provide oraquick fingerstick test. I was told it is 2nd generation. Also told to test on 3 months mark (I was in 9 weeks mark).
I am also taking antibiotics now. Does it interfere somehow?