Epi Night School Lesson 8: Screening Tests… Sensitivity, Specificity, and Predictive Values

You really should confirm that at-home test with your healthcare provider.

Welcome back to Epidemiology Night School! By now, you’ve learned how to measure risk, interpret associations, and question whether two things are truly related or just coincidental. Today, we’re diving into one of epidemiology’s most practical tools: screening tests, those handy tools that detect diseases early and save lives.

But not all screening tests are created equal. Behind every test is a story of how good it is at detecting a disease (sensitivity), how well it rules out false alarms (specificity), and how much you can trust a positive or negative result (predictive values). It’s like trying to find Waldo in a sea of red and white stripes: you want a test that can reliably spot him without mistaking random people for him.