"Because SCIENCE!"™
The FDA now says you can't rely on antibody tests to evaluate immunity from the coof ESPECIALLY IF YOU'VE HAD THE JABS.
Thanks, SecAmndmt.
Also, please note that the FDA is not the producer or manufacturer of the tests, either for :
(#1)diagnostic (determine the level of infection), or
(#2)screening of active, or even asymptomatic individuals.
Rather, the FDA relies on "Test developers (who) gather evidence to support their test's use and submit this evidence to the FDA.
When the FDA issues an emergency use authorization (EUA) for a test, it means that the FDA reviewed scientific and clinical evidence to determine
that the test may be effective when used as authorized, such as to diagnose individuals with SARS-CoV-2."
Under emergency conditions, one wonders how thorough the FDA evaluated "the scientific and clinical evidence" of either the testing,
or the actual vaccination jab in their rush to get both out into the population.
According to my understanding, the clinical trials for the vaccine was approximately 2 months; I have no information about the length of clinical testing trials.