> For those not in the lab business: a low false positive rate and a high false negative rate are useful for confirmatory testing, not for screening. Such tests

> For those not in the lab business: a low false positive rate and a high false negative rate are useful for confirmatory testing, not for screening. Such tests are terrible for screening. Newbie question: wouldn't a test with very few false positives, but frequent false negatives, still be good for screening if it was cheaper/easier than existing screening, so it could be given to more of the population based on a weaker suspicion threshold? Like, in the limit of it being free and having zero false-positive rate, you'd give it to everyone. (Maybe given your expertise it's obvious to you that the test is sufficiently expensive that this argument doesn't apply?)