The prior authorization workflow guide, end to end

Prior authorization has one shape across every specialty and every payer: capture the order, assemble the packet, submit it, track it, and respond to the outcome. The specific documentation changes by specialty and payer; the workflow does not. This guide walks the full workflow with concrete steps at each stage, and is the reference page for RCM, patient access, and call center teams running PA programs.

The prior authorization lifecycle

Every PA moves through four phases regardless of specialty: order capture and eligibility, clinical packet assembly, submission, and status tracking through outcome. On an adverse outcome, the workflow branches into peer-to-peer review, appeal, or both. This guide walks each step and shows where automation replaces manual work.

Step 1. Order capture and eligibility verification

PA starts with the order from the provider: procedure, CPT/HCPCS codes, ICD codes, scheduled date (if surgical), and ordering provider. Before anything else, eligibility and benefits verify whether the payer requires PA for this specific combination. Insurance eligibility verification returns benefits, PA requirements, and network status. Most denials prevented at this stage: "PA not required," "service not covered," "provider not in network." The 271 response from an eligibility check is the first source of truth.

Step 2. Clinical packet assembly

The clinical packet is the core of the PA. Contents vary by procedure and payer but typically include: diagnosis documentation (clinical notes with the specific ICD), imaging or lab supporting the diagnosis, documented conservative-therapy history (when required), functional-status measures, and the procedural plan. For surgical PAs, the surgeon\u2019s operative plan or consultation note. For drug PAs, the prescription details, prior drug history, and step-therapy documentation. For imaging, the referring-provider note and AUC score if required by the RBM.

Packet completeness is the single biggest predictor of first-pass approval. Incomplete packets return for more information, which costs 3-7 days of additional cycle time. AI document agents that pre-check packet completeness against the payer\u2019s requirements close most of this gap.

Step 3. Submission across three channels

Submission flows through whichever channel the payer supports for this request: electronic PA (X12 278, HL7 Da Vinci PAS FHIR, NCPDP SCRIPT for pharmacy), portal (Availity, eviCore, Carelon, payer-direct), or phone/fax for payers without digital submission. Modern PA platforms use electronic where available and browser automation for portals, falling back to voice when the phone is the only option. See PA portals and UM vendors for the full infrastructure map.

Step 4. Status tracking cadence

Most payers do not push status updates. Status has to be pulled. The right cadence depends on urgency and scheduled service date: scheduled surgery in 7 days = daily status polling; routine referral = every 2-3 days; stat requests = every 4-6 hours for the first 24 hours. Flexbone runs status polling as a background workflow with automatic escalation when a request stalls. The escalation path (see below) preserves payer relationships while forcing movement.

Peer-to-peer review: scheduling and prep

A peer-to-peer (P2P) review is a phone conversation between the ordering provider and the payer\u2019s medical director (or delegate physician). P2P is usually offered when the payer\u2019s UM nurse cannot approve based on documentation alone, or after a denial. P2P must happen within a narrow window (typically 24-72 hours after offer); missing it forfeits the option.

P2P scheduling is an operational bottleneck. The ordering provider is typically in clinic or in the OR. The payer\u2019s medical director is available in narrow windows. Flexbone\u2019s voice agent handles the scheduling back-and-forth, confirms the window with the provider\u2019s office, and calls the provider at the scheduled time. Prep includes: the chart summary, the specific medical-necessity criteria the payer uses (usually MCG or InterQual), the talking points mapped to the criteria, and the specific clinical ask. Providers walking into P2P with this prep have substantially higher overturn rates.

Denial appeals: first-level and external review

A denial opens an appeal window. The specific window varies by payer and by state: typical commercial internal appeal is 180 days, Medicare traditional is 120 days, MA is 60 days, Medicaid varies by state. Appeal content: the denial letter, the clinical packet including any documentation the payer said was missing, a cover letter addressing the specific denial reason, and cite-by-cite refutation of the payer\u2019s criteria application.

If first-level internal appeal is denied, options depend on the payer: second-level internal appeal at some payers, external review through state insurance department or the independent review organization (IRO), ERISA appeals for self-funded plans, state-specific appeals for Medicaid, CMS Quality Improvement Organization (QIO) for Medicare. External review overturn rates are meaningful (20-40 percent depending on case type), so strong second-stage work pays off.

Flexbone\u2019s denials management agent ingests denial letters, categorizes the denial reason, pulls the refutation packet, and generates the appeal cover letter tailored to the specific denial. Human review approves before submission. On high-stakes cases, the appeal goes back through the workflow with provider signature.

Denial reasons and how to prevent them

Most PA denials fall into a small set of categories. Understanding the distribution helps target prevention. Common reasons and typical prevention:

• Missing clinical documentation. Most common. Prevented by packet-completeness check before submission.
• Failed step therapy / conservative therapy. Prevented by pulling the complete therapy timeline from the chart.
• Not medically necessary per payer criteria. Prevented by matching the submission against MCG or InterQual before submitting; if mismatched, escalate to P2P rather than submit-deny-appeal.
• Service not covered. Prevented at eligibility check before the visit.
• Out of network. Prevented at eligibility; sometimes addressed with a single-case agreement.
• Duplicate request. Prevented by checking for existing authorization before submission.
• Wrong CPT / HCPCS. Prevented by coding review before submission.

Medical necessity criteria: MCG, InterQual, Hayes, and payer policy

Most commercial and MA plans use MCG Health (formerly Milliman) or InterQual (owned by Change Healthcare/Optum) criteria for utilization management. MCG has Inpatient/Surgical, Ambulatory, Behavioral Health, Home Care, and Ongoing Management criteria. InterQual has Acute Adult, Acute Pediatric, Behavioral Health, Level of Care, and Procedures. Hayes (Hayes Inc.) publishes technology-assessment evidence that some plans use for emerging procedures and investigational-technology denials. Individual payer medical policies (e.g., UHC Medical Policy, Aetna Clinical Policy Bulletins) layer over the UM criteria.

Matching your packet to the specific criteria language in MCG or InterQual is the core skill of effective PA. The AI document agent pulls the relevant criteria version, maps chart documentation to each required element, and flags gaps before submission.

Escalation playbook

When a PA stalls, the escalation path depends on urgency and channel: (1) re-submit with additional documentation if the initial submission returned a clarification request, (2) call the payer provider line to check status and request expedite, (3) escalate to a supervisor at the UM vendor or payer, (4) offer or request peer-to-peer, (5) file an expedited internal appeal if the clinical urgency supports it, (6) contact the state insurance commissioner for egregious cases, (7) file an external review or IRO request after internal appeal exhaustion. Each step has its own documentation requirement and timeline. Automation gets you reliably through steps 1-3; the clinical-judgment steps stay with humans with AI-prepared packets.

Where Flexbone fits

Flexbone runs the full workflow: order capture, eligibility verification, packet assembly, submission (electronic, portal, voice), status tracking, P2P scheduling, denials ingestion, appeal generation, and escalation. Document agents handle packet assembly and appeal drafting. Browser agents operate portals. Voice agents handle phone lines and P2P scheduling. See the full PA platform.