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by spease 608 days ago
> From what I understand, an antigen test is still a stool test, meaning they are only 50% accurate.

“Accuracy” is too vague. You want to find out what the sensitivity and specificity are.

https://ebn.bmj.com/content/23/1/2

For instance, a rapid covid test might have low sensitivity but high specificity. Meaning if it’s negative, you could still have the disease. But if it’s positive, you’re almost certainly sick. Ie the false negative rate is a lot higher than the false positive rate.

2 comments

Technically a "rapid covid test" only detects the presence of certain viral genetic material. This usually means the patient is or recently was infected with SARS-CoV-2 (the virus) but it doesn't indicate anything about whether the patient has COVID-19 (the disease). Many infections are asymptomatic and thus not medically classified as a disease state.

This distinction might seem pedantic but it's important to be precise when discussing medical issues.

If you want to be precise… There are different types of “rapid COVID test”, the most popular of which detect antigens, not ‘viral genetic material’. PCR tests detect genetic material. Both tests seem to have differing levels of sensitivity to each variant of the virus.
Stool tests are questionable to begin with.