Multi-cancer early detection blood tests, designed to identify cancer signals from a single blood draw, are rapidly gaining interest from patients, employers, and health systems — despite the fact that none are yet approved by U.S. regulators. In a detailed examination, The New York Times reports that demand is accelerating even as physicians and researchers remain uncertain about how these tests should be used, interpreted, or paid for.
The most prominent test, Galleri, has now been prescribed more than 420,000 times, according to its manufacturer, GRAIL, which plans to seek FDA approval in 2026. Proponents argue these tests could help detect cancers that lack routine screening options. Clinicians have shared compelling individual cases where early detection prompted earlier treatment.
However, the broader evidence base remains limited. In large studies, a substantial portion of positive results later proved false, and the tests missed more cancers than they detected. Experts caution that false reassurance from negative results may delay proven screenings such as colonoscopy, while false positives can trigger anxiety, invasive follow-up testing, and unnecessary costs — without clear proof that these tests reduce cancer-related deaths.