I have a question about HIV blood test?

i asked a HIV question before but i wanna ask something....if the window period is over (means that HIV anti-bodies can be detected in blood) and a person has HIV and the person makes HIV blood test then...could the result be negative by mistake or the result shows positive for sure?? i know that when a test shows negative then they make another test which is more sure but...are all tests done to the person for HIV show the true result in the end?? because i had sex while using condoms once and after like a year which means the window period for HIV will be over i had a blood test for HIV and the result was negative....so i wanna know...somebody tell me plz a sure and correct answer

The Western Blot test confirms by finding certain antigens like p24. This test is done after a positive test for HIV.
The PCR test for viral load of HIV virus is the most accurate.
This is assuming that you are NOT taking any ant-viral medications to suppress the replication of the HIV virus. I have seen a negative HIV antibody test and an indeterminate Western Blot test. This is because any band seen on the Western Blot test will result in an indeterminate result. This particular case the patient ordered it separately because a negative HIV test will not go to Western Blot. I have also seen a negative HIV test and a positive Western Blot. This particular case the patient's white cell count was so low that no antibodies were made ( very critical-- end stage of AIDS)

The best thing to do if you are still worried about your test result being a false negative is to ask for the HIV ultra viral load test by PCR. I again say that I am assuming you are NOT taking any anti-viral medications. This will detect the smallest number of viral particles in your blood.

if you window period is over and you take your test a gain and its negative then you don't have to get further testing your in the clear your negative