Regulatory
Electronic Prior Authorization: A Plain-English Guide to the FHIR PA API
What HL7 Da Vinci PAS, CRD, and DTR actually do, how they connect your EHR to payers, and what changes for your front office in 2027.
April 21, 20268 min readApproveMD Team
Electronic prior authorization (ePA) replaces fax-and-portal workflows with a real-time API conversation between your EHR and the payer. The HL7 Da Vinci project defines three building blocks: CRD, DTR, and PAS.
CRD, DTR, and PAS
- CRD (Coverage Requirements Discovery): tells the EHR if a PA is needed at the moment of ordering.
- DTR (Documentation Templates and Rules): pulls the exact documentation the payer requires from the chart.
- PAS (Prior Authorization Support): submits the request and returns the decision.
What changes for your front office
Most clean requests will be approved in seconds, at the point of order. The work that remains is the gray area: peer-to-peers, appeals, and clinically complex cases. That's exactly the work an experienced PA specialist handles best.
Want this handled for you?
We run prior authorization for independent practices with a 90%+ first-pass approval rate. Free 30-minute audit, no commitment.
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