Statements like this are not only false but dangerous as it undermines those trying to save lives. I've talked to a nurse about this, and tests don't just sit around to be sent in blank. They have to be ordered from the lab for a specific patient by a doctor. This is just unsubstantiated rumor that I keep hearing without a shred of proof.
Oh and the hospital she works at has a full Covid unit and people die regularly from the disease. Please take this seriously.