According to Which Criteria Should the Undiagnosed Diseases Network's Value Be Assessed?

The Undiagnosed Diseases Network (UDN) exists at an intersection of diagnostic research and clinical care and has 2 main goals: to advance diagnostic science and to facilitate accurate diagnoses in individual patient-participants with rare conditions or so-called "medical mysteries." The value of the UDN's translational research and clinical application model and of the results it produces derive from whether and to what extent the UDN achieves its 2 goals. This article considers criteria currently used to assess achievement of those goals, identifies their merits and drawbacks, and offers strategies by which the UDN might further advance diagnostic science and individual patient-participants' interests.