Definitely not "we won't do anything about it". The medical industry (and frankly many other things but especially the medical industry) needs to find an effect

Definitely not "we won't do anything about it". The medical industry (and frankly many other things but especially the medical industry) needs to find an effective way to present the common result "this test returned positive, but given the base rate in the population and the accuracy of this test, this is not necessarily enough information and your probability of having X is still only Y%, so we're going to run another non-invasive test to see if there's even enough information to warrant doing a more detailed check; ZZ% of people get a negative on the second test". Perhaps find a nice graphical presentation of the simplest version of Bayes Rule: "the base rate in the population is this, here's what the test means for the part of the population that doesn't have it, here's what the test means for the part that does, here's how your probability went up but that it's still vastly more likely you don't have it than that you do."