HIV Instant Rapid Tests

Hi everybody, it seems like a lot of people on the forum have had a mixture of blood tests and the instant rapid tests to see whether they have HIV. Is one more reliable than another?

Also, I had the HIV Insti Test (in London) which the clinic said was 99.9 percent accurate after 3 months.  I understand the test uses blue dots to identify negative and positive infections (one for negative and two dots for positives).  I had a single blue dot appear on my test, and from what I can remember, I did not see the second blue dot, the doctor who carried out the test also confirmed that the test was negative.

My question was, would the second dot be as bright as the single dot, or can the dots sometimes appear faded, and therefore difficult to see at times? I know I should have asked to see the test again at the time, but didn't. Has anyone ever heard of these insti rapid tests being misinterpreted as a false negative?

Thanks in advance to you all.

[Teak]

One dot tells you that the test is working, "control dot" and no other dots tells you that you are negative. You are conclusively negative.