Can I ask why you would be so insistent on testing? Did you change treatment based on a positive test result?

When my son tested positive, they refused to let us re-test to see if it may have been a false positive. He's 2 and was completely asymptomatic.

SO insisted on the testing, not me, because she works around a lot of other people and children and did not know if she was contagious.

She also thought it would be helpful to know if exposure = any additional immunity down the road, since all of the facts constantly change

In our area, when kids test positive, they don't have to be tested for many weeks after. I know several that tested positive a few weeks before Omicron hit, then were refused when they eventually had Omicron symptoms.

PCR false negative rate is really low.

There are other possibilities like that she had a cold and the 5th test was a false positive or she had a cold and got covid several days later.

so, in that case, which test was the error? negative or positive?

seems like she has covid ¯\_(ツ)_/¯