I posted about this awhile ago. The test is accurate
by dulac89 (2020-06-21 18:09:14)

In reply to: CDC reported half of the anti-body tests were inaccurate  posted by Wolfetone


But when applied to a disease with low prevalence even going from 99 to 98% sensitivity decreases positive predictive value considerably

For all these tests a negative is for all practical purposes a true negative. But until disease prevalence increases PPV will remain lower