For a cancer screening test to be meaningful, it requires high sensitivity (e.g., 80%) and very high specificity (e.g., 99.5%) to achieve a high positive predictive value and a reassuring negative predictive value, especially when the pre-test probability is low (e.g., 1%).

“this is that if someone has a pre-test probability of one percent i mean it sounds crazy you're going to need 80 sensitivity and 99.5 specificity to say this is a test that matters this is a test where okay now my positive predictive value is high enough that i can do something with this and just as importantly my negative predictive value means i can breathe easy right”