Most ePA platform marketing collapses three Da Vinci pillars into one bullet point. The reality is that Coverage Requirements Discovery (CRD), Documentation Templates and Rules (DTR), and Prior Authorization Support (PAS) are three separate FHIR specifications, each with their own conformance suite. A platform that ships only one or two of them leaves the payer to glue the third in place, which is where ePA programs lose 2026 timelines. This piece looks at platforms that actually deliver the full CRD / DTR / PAS triad as production-grade software in 2026, and where each one has gaps worth knowing about.
If you want a broader survey before this, the ePA stack reference is the entry point on this site for all the moving parts.
What "Full CRD / DTR / PAS" Actually Requires
A complete ePA triad has three working endpoints and a SMART app to bridge them. CRD answers the EHR's order-time question (is PA required, what documentation is needed). DTR renders the payer-specific Questionnaire inside the provider workflow and runs the CQL rules. PAS submits the completed bundle and returns the decision. Platforms that ship only the PAS endpoint, expecting the payer to source CRD and DTR separately, are not full-stack. Reading the conformance reports from Da Vinci Connectathon events is the fastest way to see which platforms are honest about coverage.
1. Smile Digital Health (Smile CDR)
Smile CDR is the most complete commercial CRD / DTR / PAS triad among FHIR-native vendors in 2026. The CRD CDS service, the DTR SMART app, and the PAS endpoint all run on the same FHIR store, which means consent, audit, and reporting are unified. The X12 278 / 275 round-trip is the weakest link; Smile typically pairs with an external X12 adapter for payers that need legacy interop. Pricing is enterprise-tier but predictable.
2. InterSystems IRIS for Health (Da Vinci suite)
InterSystems shipped a Da Vinci suite that covers CRD, DTR, and PAS as part of the broader IRIS for Health stack. The strength is the unified data platform underneath; analytics, care management, and ePA all read from the same FHIR store. The weakness is a longer integration timeline (typically 12-18 months) and the enterprise commercial model. Bigger payers with on-prem hosting requirements end up here.
3. Edifecs ePA (with FHIR Layer)
Edifecs built the FHIR ePA layer on top of its X12 base. CRD and DTR are present but feel newer than the PAS implementation, which inherits decades of X12 278 / 275 maturity. Health plans whose UM systems are X12-native treat Edifecs as a natural extension; FHIR-first plans evaluating Edifecs alongside Smile or 1upHealth often find the SMART app experience less polished.
4. 1upHealth ePA Module
1upHealth shipped a complete CRD / DTR / PAS triad in 2025 and has been iterating on the DTR SMART app heavily during the 2026 implementation cycle. The platform is FHIR-native end to end, the developer documentation is among the cleanest, and PMPM pricing keeps the entry point low. The trade-off is that 1upHealth came from the patient and provider API side, so the UM-system integration tooling (for the back-office adjudication path) is less mature than at Edifecs.
5. Reference Implementations (HL7 Da Vinci)
The HL7 Da Vinci reference implementations are open-source and exist for CRD, DTR, and PAS. They are useful for testing, conformance work, and as a starting point for in-house builds. They are not production-ready out of the box; payers that go this route invest significant engineering time turning the reference code into a hosted service with SLAs, audit trails, and operations support.
How to Read the Differences
The honest framing for selection is that the choice rarely comes down to a single feature gap. It comes down to where the payer's existing investment sits, how aggressive the timeline is, and whether the FHIR data store is meant to do work beyond compliance.
If you want a tighter shortlist of just the PAS implementation tools, the Top 5 Da Vinci PAS implementation tools list narrows it down. And for the X12 chain question specifically, the FHIR ePA solutions that handle X12 278 / 275 round-trip breaks the X12-FHIR mapping down by vendor.