The 2026 ISA: ONC Drops a Catalog, Founders Should Read It Like a Term Sheet
Quick Links: Knowledge Base, Podcast, and Social
Knowledge Base — search and filter every article and podcast episode by topic, section, and keyword: kb.onhealthcare.tech
Listen to the Podcast — every article is also available as an audio episode. Free subscribers get the public episodes; paid subscribers get the full archive including subscriber-only episodes. Listen on Apple Podcasts, Spotify, or browse all episodes on the Substack Podcast page.
For paid subscribers — your subscription unlocks the entire research archive (538+ deep-dives), every paid podcast episode, and full search inside the Knowledge Base. To listen to paid episodes in Apple or Spotify, link your Substack subscription via the show settings on those platforms (instructions inside the Substack app under Subscriptions → Podcast).
For free subscribers — free posts and free podcast episodes are always public on Apple/Spotify and Substack. Upgrade any time at onhealthcare.tech/subscribe to access the paid archive and paid episodes.
Follow on Social — X · YouTube · TikTok · Instagram
Abstract
Published: March 2026, ASTP/ONC (Office of the National Coordinator for Health Information Technology)
What it is: The Interoperability Standards Advisory (ISA) is ONC’s annual catalog of health data interoperability standards and implementation specs. The 2026 Reference Edition is the stable annual snapshot of that catalog, published alongside a wave of other major policy outputs in Q1 2026.
Key concurrent developments driving the relevance of this edition:
- Draft USCDI v7 released Jan 29, 2026, adding 30 proposed data elements (29 new plus one major revision), bringing the total proposed element count to 156
- HTI-5 proposed rule (Dec 15, 2025): major deregulatory rewrite of ONC certification, going FHIR-first
- Diagnostic Imaging Interoperability RFI (Jan 30, 2026): ONC asking industry what to do with DICOM and imaging standards
- USCDI v3 became required as of Jan 1, 2026 (94 data elements mandatory for certified HIT)
- SVAP 2025 approved standards include USCDI v5 (156 total elements), available voluntarily as of Aug 29, 2025
- Comment deadlines: USCDI v7 closes April 13, 2026; HTI-5 closed Feb 27; Imaging RFI closed March 16
Why it matters: This edition lands at an inflection point where ONC is simultaneously raising the data floor (USCDI v3 required), sketching a higher ceiling (USCDI v7 draft), deregulating the compliance box-checking (HTI-5), and openly asking what to do about 30+ years of DICOM files sitting in siloed PACS systems. For entrepreneurs building on health data and investors placing bets in that space, Q1 2026 is a policy burst that reshapes the data infrastructure layer.
Table of Contents
Section 1: What the ISA Actually Is and Why It Gets Ignored
Section 2: The Standards Stack Right Now, Honestly
Section 3: USCDI v7 Draft Breakdown and What It Signals
Section 4: HTI-5 Changes the Game for Developers
Section 5: Imaging Is the Next Frontier and It Is Wide Open
Section 6: Investment Implications and Where the Bets Are
What the ISA Actually Is and Why It Gets Ignored
Most people in health tech either pretend the ISA doesn’t exist or treat it as background noise in a compliance email from their legal team. That’s understandable. The document is basically a giant table of acronyms mapping interoperability use cases to standards. USCDI, FHIR, HL7 v2, C-CDA, SNOMED, LOINC, RxNorm, X12, NCPDP SCRIPT, DICOM, and about sixty other things you’ve either heard of or actively tried to forget. ONC breaks the catalog into more than sixty subsections organized by use case: clinical care, lab, imaging, public health, pharmacy, admin, patient demographics, and so on. Each entry gets a maturity rating and an adoption level, which is ONC’s honest attempt to tell you whether a given standard is something real people use or just something a standards development organization published to a mailing list in 2009.
Here’s the thing though: the ISA is effectively the regulatory substrate for health data infrastructure investment. It’s not a mandate in itself. ONC is explicit that being listed in the ISA does not require implementation. But what the ISA does is define the vocabulary, signal ONC’s directional intent, and anchor everything from certification criteria to payer rules to TEFCA participation requirements. When CMS’s Prior Authorization final rule (CMS-0057-F) says payers must expose data via FHIR APIs, it’s the ISA-adjacent standards stack that defines what “FHIR” means operationally. When a developer wants to get ONC-certified, the standards in the ISA are the same standards that end up in certification criteria. The ISA is not just documentation. It’s the genome of what the health data layer is supposed to look like.
The 2026 Reference Edition drops at a genuinely busy policy moment. Three major overlapping ONC outputs landed within about six weeks: the HTI-5 proposed rule on December 15, 2025, Draft USCDI v7 on January 29, 2026, and the diagnostic imaging RFI on January 30. The 2026 ISA is the stable reference snapshot that industry players can point to in contracts, grant applications, and vendor agreements while all that activity is in flight. So even if the document itself reads like an encyclopedia of three-letter acronyms, it matters as the settled floor of what is real and expected right now.
The Standards Stack Right Now, Honestly
