What does 'sensitivity' mean in the context of a cancer screening test?

Sensitivity is the proportion of people who truly have cancer that the test correctly identifies as elevated (positive). A test with 97% sensitivity correctly identifies 97 out of 100 true cancer patients as positive, while missing 3 (false negatives). In cancer screening, high sensitivity is critical because missing a cancer (false negative) can delay treatment when cure is still possible. OncuraKit's per-marker sensitivity is 93.8% for miR-21, 81.5% for miR-375, and 97.3% for miR-141. Because all three markers are measured and a cancer patient typically overexpresses at least one, the combined panel sensitivity is higher than any individual marker alone. For comparison, Galleri (Grail) achieves 16.8% sensitivity at Stage I — meaning it misses 83 of 100 early-stage cancer patients.