Are COVID tests accurate?

[fairyannie]

If not - what causes them to be inaccurate?

FIL tested positive in October along with MIL and 4 of their friends.

He's recently been fast tracked for cancer tests, turned up for scans and tested positive today?

He's so worried that a diagnosis is now being delayed further as he has to isolate for 10 days.

How can this happen?

You arent supposed to test within 90 days of a positive test (if you don't have symptoms) as residual virus can cause a positive test even though you aren't contagious

So why aren't the hospital aware of this?

If he isn't contagious why was he sent home and told to isolate without doing the tests?

Did they know he had tested positive before?

If you've had a positive PCR test within the last 90 days

You should not have a no symptoms test if you've had a positive PCR test in the past 90 days. If you've never been tested, have tested negative before, or if have tested positive more than 90 days ago then you can take the tests.

Yes - he said he'd tested positive and gave the date of the test.

But he was sent home - for another period of isolation.

He has absolutely no symptoms 🤔

Online gives this explanation for not testing within 90 days if there are no symptoms:

This is because fragments of inactive virus can be persistently detected byPCRin respiratory tract samples for some time following infection.

You would only get tested within the 90 days if you had symptoms

There have been confirmed cases of reinfection within less than 90 days so they can't be sure that it's just residual RNA from the infection in October. Cancer diagnostics are an area where they need to be extra vigilant in keeping the virus out as some types of cancer can put you on the ECV list.