Table 1 RD-CODE diagnosed and undiagnosed status by type of diagnostic ascertainment. In the framework of RD-CODE, the “undiagnosed patients” term is used to describe patients with no established clinical diagnosis. “Diagnosed patients” have an established clinical diagnosis related to a confirmed rare disease, even without an etiological diagnosis

From: Coding undiagnosed rare disease patients in health information systems: recommendations from the RD-CODE project