Submit an X12 278 prior authorization request for a non-urgent outpatient procedure including all required clinical and diagnosis loops and handle a pend response with an additional documentation request
Build the hierarchical level structure with HL01 through HL04 representing information source, subscriber, dependent if applicable, and event level; the event level is specific to the 278 and carries the service review information
Populate the UM segment at the event level: UM01 is the request category code distinguishing initial authorization from reconsideration or appeal, UM02 is the certification type code, and UM09 is the level of service code indicating outpatient versus inpatient
In the 2000E health care services review information loop, add HI segments with the appropriate diagnosis qualifier codes for the primary and secondary diagnoses supporting the medical necessity of the requested service
In the 2000F service loop, populate SV1 or SV2 with the procedure code and units requested, and add HSD segments to specify the requested quantity and unit of measure such as visits or days
When the 278 response returns with an HCR01 action code indicating pend status, extract the AAA or MSG segment content that identifies what additional documentation the payer requires, and note the CTN or REF segment containing the payer-assigned review reference number
Resubmit the request as a 278 reconsideration using the original review reference number in REF and attach the clinical documentation reference in the PWK segment specifying the attachment transmission method
Known gotchas
The UM segment certification type code distinguishes initial request from appeal or reconsideration; submitting a reconsideration with the initial request code causes the payer to create a duplicate authorization request instead of linking it to the original pending review
Some payers require the attending physician NPI in a specific NM1 loop within the 278 and will pend the request with a generic informational status code rather than an explicit error if the loop is absent or malformed
A pend response with an action code indicating additional information is required is not a denial and does not restart the timely filing clock; however, many practices incorrectly treat pends as denials and submit new authorization requests, consuming additional clinical review capacity
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp