[marktwain]

Influenza virus and SARS-CoV-2 are as similar to one another as humans and snails. They aren't even in the same phylum. There is zero chance of any testing failing to distinguish between the two.

If your claim is correct, then how is it there have been so many documented cases of false positives for SARS-CoV-2?

(Reuters) - The U.S. Food and Drug Administration said on Tuesday it is alerting clinical laboratory staff and healthcare providers that false positive results can occur with COVID-19 antigen tests.

[2aProtectsTheRest]

"If your claim is correct, then how is it there have been so many documented cases of false positives for SARS-CoV-2?"

Two things:

1. False positive means something caused a test to show positive in a sample that should test negative. That something can be contamination from other sources containing things that never should have been in the sample and thus are beyond the scope of the testing. For example, if I dip a test strip in a strong acid, that may trigger a positive result. Since you should never have a bunch of acid in your nasal cavity, that's beyond the scope of proper testing procedure.
2. The linked article is about antigen tests. That's not the same as the RT-PCR test which is considered the "gold standard" and is used as part of the CDC's case definition for COVID-19. The rapid antigen tests are known to be less accurate, but they're quick and cheap. Those are the tests that gave Elon Musk contradictory results. The RT-PCR test confirmed he was actually positive.