Blood-based cancer tests with 50% sensitivity and 99.5% specificity do not significantly improve cancer risk assessment in low pre-test probability populations and have a high risk of false positives.

“this issue that um something that you know sounds great 50 sensitivity 99 specificity even ignoring for the fact that the stage one sensitivity is actually less than five percent but just let's just say on the surface the 50 percent where it's where we're at um that if you already basically have no risk of uncancer you're you know less than one percent chance of having cancer the test isn't moving really moving the needle for you significantly and uh has a high risk of catching um false positives as you mentioned because the positive predictive value isn't so good um and that leads to lots of further testing anxiety often we can't find anything but then patients are worried for years that is there something brewing is it just the next scan will show it or the next time”