Grail's Cancer Misdiagnosis and Promising Blood Test Study

More than 400 patients who signed up for Grail's pioneering oncology detection test received erroneous letters last month suggesting they may have developed cancer. The letters were sent "in error" by its telemedicine provider PWNHealth. Grail said the letters were in no way related to or caused by an incorrect Galleri laboratory test result. The incident has generated concern among some insurers who are trialing Galleri, a multi-cancer early detection test that claims to be able to spot more than 50 cancers from a single draw of blood.