State Health Information Exchanges in the US sit on top of a master patient index whether they advertise it that way or not. Pulling records from dozens of EHRs, clinics, labs, and pharmacies across a state and stitching them together into a single patient view is the MPI problem at its hardest setting. The MPI tool a HIE picks is going to shape the participant onboarding experience, the data quality story for years to come, and the cost profile of every cross-system query the HIE handles.
This list covers five MPI tools that have a defensible story for state HIE deployments in 2026. For more on healthcare data exchange, the homepage covers the broader interoperability landscape.
What State HIEs Ask of an MPI
State HIE operators face MPI work at three structural levels of difficulty. The volume is large, since the index has to span every participant in the state. The participant heterogeneity is high, since each EHR sends data with slightly different identifier conventions. And the cross-state edge cases are common, since US patients move and seek care across state lines more often than the original HIE designs assumed.
For the broader picture of what an MPI has to do, the master patient index buyer's guide is the right primer.
The 5 Tools to Know
NextGate's enterprise MPI is the long-running pick for US state HIEs. The product has been deployed in HIE settings for over a decade, the operational story is well-trodden, and the matching algorithms have been tuned against the kind of demographic data state HIEs actually receive. The trade-off is the enterprise procurement timeline.
Verato has become a strong commercial pick on the back of its referential matching approach. The product uses a reference identity database built from third-party sources to anchor the matching, which can lift recall on records with degraded demographic data. The trade-off is the data residency conversation that referential matching raises.
Mirth Match, paired with the wider Mirth integration stack, is a defensible pick for HIEs that already run Mirth for the rest of their integration work. The product handles standard matching workloads, the integration with the wider HIE plumbing is clean, and the operational story is familiar.
OpenEMPI is the long-running open-source MPI line that has been deployed across several US state HIEs. The product is unglamorous, but the matching engine works, the audit trail is defensible, and the licensing cost is zero. The trade-off is the engineering team you need to operate it.
Smile Digital Health's MPI bundles patient matching with the Smile FHIR platform. For an HIE that wants a single vendor for the FHIR layer and the MPI together, the integration story is the strongest in the field. Cost is the trade-off.
What to Test Against a State HIE Workload
A few targeted tests will tell you whether an MPI tool holds up.
- Run the matching engine against a ten-thousand-record sample drawn from three different participants and verify the recall and precision against a hand-validated reference.
- Add a participant with non-standard demographic conventions and confirm the matching adapts without a custom integration project per participant.
- Walk through a cross-state edge case, where the same patient appears with conflicting addresses, and confirm the matching produces a defensible result.
- Pull the audit log for the test traffic and verify the chain of custody is intact for each merge.
Tools that pass those four are tools that will hold up under HIE workload. Tools that fail any of them produce duplicate records that show up as quality complaints from participants.
How to Pick
For enterprise-grade HIE deployments, NextGate and Verato are the strongest picks, with Verato bringing the referential matching edge. Mirth Match fits HIEs that already run Mirth. OpenEMPI is the right answer for HIEs with engineering capacity that want to avoid recurring license cost. Smile fits HIEs investing in a unified FHIR platform. The natural next read is the Top 5 EMPI engines for cross-system patient lookup.
Sources
- Role of MPI and Record Locator Services in HIE implementation - PDF, AHRQ
- Interoperable Digital Identity and Patient Matching v2.0.0 - HTML IG, HL7 FHIR FAST Identity team, 2025
- TEFCA Qualified Trust Framework 2.1 draft - PDF, Sequoia Project RCE, December 2025