Thank you
@biobook. Yes, it was a different test, I don't know which, I only remember positive was over 15. I was merely curious since 594 seems like such a high number that I was wondering if there was a reexposure that made the numbers go up. Or if that was considered lower than the 123 on the first test, as would be expected 7 months later.
The 2nd child was tested at least 6 times for covid and once for antibodies while our family was sick, and all were negative. Interesting theory that she had it first, but we all tested for antibodies in January, and that child was negative then as well.
Even if somehow she got it asymptomaticly months after us, I would think she would have higher antibodies than 1, so maybe the test being wrong is the most likely answer.