Medical AI tools fall into five steps, ordered by how close each one gets to making the medical decision itself. From least to most: writing notes (typing up what was said at a visit), paperwork (insurance pre-approvals, summarizing a patient's records), spotting risk (flagging which patients a doctor should check), suggesting a diagnosis (proposing what's wrong) and acting alone (caring for the patient with no doctor involved). The FDA, the U.S. agency that approves medical products, is moving toward judging each finished tool by what it does, rather than by the general-purpose AI underneath it. The higher the step, the more checking a tool faces. A note-writing tool needs only the doctor's signature on the note. A tool that reads medical scans needs FDA sign-off.

At the bottom step, note quality no longer separates the tools. Most now write notes that are about equally good. Abridge, Ambience and Nabla are moving into billing codes and insurance pre-approvals. Epic, whose patient-record software many hospitals run on, is building its own note-writer (high confidence). Near the top, Aidoc is betting that one general system can spot many conditions. Viz.ai stays with a few. It also holds its own Medicare payment codes, so hospitals get paid extra when they use it. (Medicare is U.S. government health insurance for older people.) That makes Viz.ai the clearest case on this list of a tool paying for itself.