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Thank you for taking an interest in the Open Client Registry (OpenCR)! This is a community project and meant for others to adopt to their use cases as they wish.


Regardless if you're just curious, an implementer, or a developer, please read the this Overview tab first and then the User Manual. We've kept them short.

What is OpenCR?

OpenCR is an open source and standards-based client registry. A client registry facilitates the exchange of patient information between disparate systems. A client registry holds patient identifers and may include patient demographic information. It is a necessary tool for public health to help manage patients, monitor outcomes, and conduct case-based surveillance.

A client registry sits within a health information exchange (HIE). An HIE is used to safely and effectively exchange information. A critical component of an HIE are registries, such as those to manage a shared, canonical facility list, practitioners, and patients.

What does OpenCR do?

OpenCR is offers the ability to:

  • Assign and look-up unique identifiers,
  • Allow connections from diverse point of service (POS) systems, such as lab systems and electronic medical record (EMR) systems, that can submit messages in FHIR,
  • Configure decision rules around patient matching.


This implementation does not allow point-of-service systems to get patient demographic information stored in the Client Registry. This is also not a Shared Health Record, nor does it contain patient clinical data.

Use Cases

The Client Registry is one component in a more complex HIS architecture needed to accomplish important use cases, such as:

  • Deduplicating patients: Sometimes patients have multiple diagnostic results stored within a POS. The Client Registry will link patients based on configurable decision rules so multiple test results for the same patient can be found.

  • Tracking patients lost to clinical care: EMRs are often not interoperable with one another, resulting in difficulty tracking patients as they move between facilities to seek care. A Client Registry will help data managers to track patients, decreasing instances of duplicate and incomplete records, patients LTFU, and sub-optimal care.


The Client Registry is not deduplicating or even touching patient clinical and demographic records within point-of-service systems. Instead, it provides a way to enable use cases like deduplication - which must be an external process.


OpenCR was developed by IntraHealth International with support from PEPFAR through the USAID MEASURE Evaluation Project. Technical direction was provided by CDC.

Last update: April 16, 2020