Prior Auth (ePA) APIs

Prior Authorization flow: three column groups — Provider EHR (CDS Hooks client, SMART on FHIR app, PAS client) on the left, Payerbox (CRD CDS service, SDC questionnaire, PAS endpoint) in the center, Health Plan (data sources, UM system) on the right — with three stage arrows labeled CRD, DTR, PAS between the groups.

Da Vinci electronic Prior Authorization stack. CMS-0057-F requires a FHIR-based Prior Authorization API by January 1, 2027. Payerbox implements the Da Vinci CRD, DTR, and PAS Implementation Guides.

Page	IG	Role
CRD	Da Vinci CRD	Discover whether prior authorization is required at the point of order
DTR	Da Vinci DTR	Collect required documentation via questionnaires driven by CQL
PAS	Da Vinci PAS	Submit the prior authorization request and receive the response

The three IGs compose: CRD identifies the rule, DTR collects the evidence, PAS submits the request.