[RD] PRISM Library: Patient Registry Item Specifications and Metadata for Rare Diseases.

Patient registries are important for understanding the causes and origins of rare diseases and estimating their impact; and they may prove critical developing new diagnostics and therapeutics. This paper introduces the [RD] PRISM resource <http://rdprism.org>, an NIH-funded project to develop a library of standardized question and answer sets to support rare disease research. The paper presents a project case-driven plan for creating a new registry using questions from an existing related registry, revising and expanding an existing registry, and showing interoperability of data collected from different registries and data sources. Each of the use cases involves the retrieval of indexed questions for re-use. Successful retrieval of questions can facilitate their re-use in registries, meaning new registries can be implemented more quickly, and the use of "standard" questions can be facilitated. The paper further discusses issues involved in encoding the sets with relevant data standards for interoperability and indexing encoded sets with metadata for optimal retrievability.