What is a 278?
The X12 278 is the electronic prior authorization transaction: the provider's request for approval of a service, and the payer's response with a decision and an authorization number.
ST*278*0001*005010X217~Start of a 278 services review request.BHT*0007*13*REQ88231*20260120*1015~Header: a request (13), with your reference REQ88231.UM*HS*I*62~A health services review (HS), initial request (I), for MRI and CT (62).HI*ABK:M5416~The diagnosis supporting the request.SV1*HC:72148*1450*UN*1~The service: CPT 72148, MRI lumbar spine, one unit.DTP*472*RD8*20260201-20260228~Requested dates: February 1 to 28.HCR*A1*AUTH55120~The response: certified in total (A1), authorization number AUTH55120.The 278 has been a HIPAA standard for decades, yet most prior authorizations still go through payer portals, utilization management vendors and fax. Payer support for the electronic transaction is uneven, and many payers need clinical questions answered that the 278 doesn’t carry well.
Request, response, and everything in between
A 278 request names the patient, the provider, the service, the diagnosis and the dates. The response comes back as approved (with an authorization number), denied, modified (fewer units or a shorter period), or pended for more information. Pended requests are where the time goes: the payer wants clinical notes or answers to its questionnaire, and the clock keeps running.
What’s changing
CMS rules now require Medicare Advantage, Medicaid, CHIP and marketplace plans to answer standard prior authorization requests within seven calendar days and expedited ones within 72 hours, and to support electronic prior authorization through APIs. Faster answers help, but only if the request was complete the first time.
Run your revenue cycle as workflows.
We are working with a small group of billing and operations teams to shape worklist. Tell us where your work gets stuck, and we'll show you how it would run.