Welcome to the HIV forum.
I am not personally familiar with the INSTI test, but it is a widely used high performance rapid HIV test in common use in the UK, Canada, and probably many other countries (not in the US as far as I know, but perhaps it has been released here as well). All the rapid HIV tests use basically the same technology and are highly reliable. To your specific questions:
1) Not true. No illess of any kind alters the reliability of HIV testing. There are theoretical concerns about advanced chemotherapy, near terminal cancer, and the like -- but even those are theoretical, not actually documented to alter HIV test results.
2) I cannot say why any particular might use venipuncture (draw blood from a vein) rather than fingerstick. Venipuncture is less painful; or perhaps they're simultaneouly offering other blood tests along with HIV. There is nothing in this that suggests reduced expertise or anything else to worry about.
3) You need to follow the advice of the provider who does the test. If your risk for HIV is particularly high, conceivably other tests would be recommended. For sure additional testing would be needed if the INSTI test gives a positive result, but negative results are 100% reliable, as long as enough time has passed for HIV antibodies to develop (usually 4-6 weeks and always within 3 months).
Regards-- HHH, MD
and I just found out in Canada, the INSTI test only test HIV-1, I had sex with a sex worker in China about 4 month ago, and what is the chance that I'm getting HIV-2?
That's a low risk exposure. If a woman has HIV, the chance of transmission averages once for every 2,000 episodes of unprotected vaginal sex. And in China, the chance any particular sex worker has HIV is low. And if you used a condom, there is no risk at all.
To my knowledge, HIV-2 is not circulating in China. And it is vanishingly rare in North America. This isn't a realistic worry.
Hi Dear Hunter, thanks for reply, that surely clear things up. I do have one more (last) question. I have feast infection on my penis, very light, I do not scratch my penis, does it still increase the chance of getting HIV?
and there's no red dots. just feel itch when I'm washing it. I do not feel itch otherwise.
and I have been having this jock itch issue for 4 years now.
So, my question is does this increase my chance of getting HIV?
Such a rash is not likely to raise the risk of HIV. Even if it does, you have to be exposed first. This doesn't change my opinion or advice.
That's all for this thread.