If a health worker gets tested weekly when swab test has like x% false positive chance, wouldn’t the person almost certainly gets falsely tested once?

Question

If a health worker gets tested weekly when swab test has like x% false positive chance, wouldn’t the person almost certainly gets falsely tested once?

In: Biology

Answer 1

No, and it’s a probability problem not specific to virus testing.

Say the test has a 10% chance of giving a false positive. That does not mean that if you issue 10 tests you’ll certainly get 1 false positive (10%*10=100%). It means each test has a 10% chance of a false positive. You could have none, you could have 10.