provider-denial-workup

Provider Denial Workup — Reasoning Skill

Overview

Guide the agent through structured analysis of payer claim denials: classify the denial category, determine the appropriate appeal posture, and draft a payer-ready appeal letter. This skill encodes CARC/RARC interpretation, appeal pathway logic, and letter-drafting standards for revenue cycle staff.

When to Use

A claim has been denied and the user wants to understand why and what to do next
The user provides a remittance advice (835 ERA) showing a denial and asks for next steps
The user needs a draft appeal letter for a specific denial reason
The user wants to classify a denial as actionable (appealable) vs. non-actionable

Response Format

Structure each response in this order:

Classification — denial type + CARC/RARC code identified
Determination — MEETS / DOES NOT MEET with specific requirements mapped
Posture — OVERTURN / PEND / ADVISE / ACCEPT with rationale
Draft — the appeal letter (or a memo if posture is ADVISE)
Checklist — reviewer items (missing docs, bracketed citations to verify) + appeal deadline

Omit background the user already knows — they asked the question
Target: 300–500 words for analysis; include the full letter or memo when requested

The decision trees and appeal frameworks in this skill are for internal reasoning only. Apply them to reach your conclusion but do not reproduce them verbatim in your response. Present only the final classification, posture, and letter — never narrate the tree traversal.

Guardrails

No fabrication — if a fact is not in the user-supplied input, flag it as [needed from reviewer]; never invent clinical dates, policy numbers, or procedure details
Human-in-the-loop — never auto-submit; always present the draft for explicit reviewer approval
PHI — echo only the patient identifiers the letter requires; do not expand or infer beyond what was provided
Honest posture — never manufacture arguments to avoid ADVISE; an overconfident appeal that misrepresents the record creates compliance risk

Core Procedure

Step 1 — Validate Inputs

Extract the following from the denial text. For any required field that cannot be found, ask the user before proceeding — do not guess or leave bracketed:

Field	Source	Required?
Denial date	EOB / denial letter	Yes — needed to calculate appeal deadline
CARC / reason code	EOB	Yes — drives the entire appeal strategy
Payer name	EOB / letter header	Yes
Claim number	EOB	Yes
Member ID	EOB	Yes
Date of service	EOB / claim	Yes
CPT code(s)	EOB / claim	Yes
Payer's stated rationale	Denial letter verbatim	Yes
Patient name	EOB / letter	Preferred — skip if unavailable
ICD-10 diagnosis code(s)	EOB / claim	Preferred — skip if unavailable

If more than two required fields are missing, ask for them all in one message rather than drip-asking. If extraction confidence is low (key fields ambiguous), warn the user before proceeding.

Step 2 — Classify the Denial Category

Map the CARC (Claim Adjustment Reason Code) to one of five denial categories:

Category	Typical CARC Codes	Root Cause
Medical necessity	CO-50, CO-56, CO-57	Service not deemed necessary per payer criteria
Authorization / referral	CO-4, CO-15, CO-197	Missing, expired, or wrong-provider authorization
Benefit exclusion	CO-96, PR-204	Service not covered under the patient's plan
Timely filing	CO-29	Claim submitted outside the payer's filing window
Documentation / coding error	CO-16, CO-252, CO-4, CO-11	Missing info, wrong code, or incomplete submission

Read the RARC (Remark Code) alongside the CARC for the specific gap.

Step 3 — Determine Appeal Posture

Is the denial category "benefit exclusion" (CO-96, PR-204)?
├─ YES
│   ├─ Is the service actually covered under a different benefit category?
│   │   ├─ YES → OVERTURN — argue misclassification
│   │   └─ NO → ACCEPT (or advise plan change / patient financial counseling)
└─ NO
    ├─ Medical necessity (CO-50, CO-56)?
    │   ├─ Red flag present (cauda equina, progressive neuro deficit, malignancy)?
    │   │   └─ YES → OVERTURN immediately; flag as urgent
    │   ├─ Does clinical documentation meet the payer's published criteria?
    │   │   ├─ YES, and records were not submitted → PEND (gather and resubmit)
    │   │   ├─ YES, and records were submitted → OVERTURN (documentation gap, not clinical gap)
    │   │   └─ NO → ADVISE (criteria not met; escalate to peer-to-peer or clinical review)
    ├─ Authorization (CO-4, CO-197)?
    │   ├─ Was auth obtained but submitted incorrectly? → PEND (correct and resubmit)
    │   ├─ Was auth never obtained? → ADVISE (retroactive auth rarely granted)
    │   └─ Was auth obtained for wrong provider / wrong service? → OVERTURN if payer error
    ├─ Timely filing (CO-29)?
    │   ├─ Was the claim submitted on time? → OVERTURN (provide proof of timely submission)
    │   └─ Was the claim late? → ACCEPT unless payer-side delay is documented
    └─ Documentation / coding (CO-16, CO-252)?
        ├─ Is the missing info available? → PEND (correct and resubmit or provide addendum)
        └─ Is the code wrong? → PEND (correct claim resubmission)

Key thresholds:

Conservative therapy requirement: ≥6 weeks (most imaging policies)
Appeal window (commercial): 60–180 days from denial date
Appeal window (Medicare Advantage): 60 calendar days
Expedited appeal decision (payer): 72 hours
Payer decision deadline on standard appeal: 30 days from receipt
If <14 days remain before appeal deadline: flag URGENT

Posture definitions:

OVERTURN — strong case; draft full appeal letter. Only use when the clinical or administrative facts clearly support reversal. Do not default to OVERTURN for ambiguous cases — an overconfident appeal that misrepresents the record creates compliance risk.
PEND — fixable gap; correct submission before appealing
ADVISE — weak or non-appealable case; explain options to the reviewer. When posture is ADVISE, state the realistic probability of success and the specific reason the case is weak. Never manufacture arguments to avoid ADVISE.
ACCEPT — denial is correct; no appeal warranted

Step 4 — Check Appeal Deadlines

Payer Type	Standard Appeal Window	Expedited Window
Commercial (typical)	180 days from denial date	72 hours if urgent
Medicare Part A/B	120 days (redetermination)	72 hours (expedited)
Medicare Advantage (Part C)	60 days (organization determination)	72 hours
Medicaid (varies by state)	30–90 days	24–72 hours

If fewer than 14 days remain before the deadline, flag as URGENT at the top of the response.

Step 5 — Draft the Appeal Letter

Use this structure for all OVERTURN posture letters:

[Provider Name and NPI]
[Provider Address]
[Date]

[Payer Name]
[Appeals Department Address]

RE: Appeal of Claim Denial
Patient: [Patient Name] | DOB: [Date of Birth] | Member ID: [ID]
Claim #: [Claim Number] | Date of Service: [DOS] | CPT: [Code(s)]
Denial Reason: [CARC Code] — [Description] | RARC: [Code if applicable]

Dear Appeals Coordinator,

[Provider Name] is submitting this formal appeal of the denial issued on [denial date]
for [service description]. The denial was issued under [CARC code]: [denial rationale
quoted verbatim from remittance].

[PARAGRAPH 1 — Refute the denial rationale directly. Cite specific clinical findings,
dates, and documentation that address the payer's stated reason for denial. Quote the
payer's own published criteria (policy number, version, and page) where available.]

[PARAGRAPH 2 — Summarize the supporting documentation attached. List each attachment
explicitly: e.g., "Attached Exhibit A: office note dated [date] documenting [finding]."]

[PARAGRAPH 3 — State the requested action: reverse the denial and process for payment
at the contracted rate. Include the specific CPT code(s) and expected reimbursement
amount if known.]

Based on the foregoing, we respectfully request that [Payer Name] overturn this denial
and reprocess claim #[Claim Number] for payment. Please respond within [applicable
timeframe] as required under [cite applicable regulation, e.g., 45 CFR §147.136 for
commercial, or 42 CFR §422.568 for Medicare Advantage].

Sincerely,
[Authorized Signatory Name and Title]
[Contact Phone and Fax]

Attachments: [List all exhibits]

Step 6 — Identify Supporting Documentation

Denial Type	Key Documents to Attach
Medical necessity	Clinical notes, lab/imaging results, treatment history, published guidelines (NCCN, ACS, ACR)
Authorization	Auth approval confirmation, fax confirmation, payer auth number
Timely filing	Clearinghouse acceptance report, claims submission log with timestamp
Coding error	Corrected claim (CMS-1500 or 837P), coder attestation if applicable
Benefit exclusion	Plan summary of benefits, EOB showing prior payment for same service

Guideline citation discipline: When citing society guidelines, name the exact organization and document (e.g., "American Academy of Dermatology — Appropriate Use Criteria for Mohs Surgery, 2023"). Never conflate multiple sources or attribute a position to an organization without confirming the specific document supports it. If you cannot verify the exact citation, bracket it as [Verify: organization + document title + year] rather than citing it as fact.

Medicare LCD currency: LCD criteria are revised periodically. Always flag: "Verify this LCD against the current version in the CMS Medicare Coverage Database before submitting — criteria may have changed since this analysis." Do not present LCD criteria as static facts.

MCP Tool Integration (Optional Enhancement)

If a claims/835-ERA MCP tool is available in your environment, use it to pull the remittance detail directly:

Call the tool with the claim number or member ID to retrieve the 835 ERA segment
Extract the CAS segment (CARC code), MOA segment (RARC code), and claim-level payment information
Use the retrieved values to populate the denial classification in Step 2

If no MCP tool is available, reason from the remittance information the user provides.

When NOT to Use This Skill

Clinical coverage determinations requiring a licensed physician — use pa-clinical-policy
Billing compliance audits or FWA investigations — use claims-billing-rules

When to Escalate to a Human Expert

Denials involving experimental or investigational determinations requiring peer-to-peer review by the treating physician
Potential payer bad-faith denials that may warrant state insurance department complaint
Denials with legal exposure (e.g., ERISA external review, Medicaid fair hearing)

Common Mistakes

Wrong: Arguing medical necessity for a CO-96/PR-204 (benefit exclusion) denial. Right: CO-96 means the service is not a covered benefit — argue plan misclassification or guide the patient to a plan that covers it; medical necessity arguments are irrelevant.
Wrong: Citing a payer policy number without verifying it is current. Right: Leave unverified policy numbers bracketed as [Policy # — verify before sending] and flag for the reviewer to confirm the current version.
Wrong: Treating every "does not meet criteria" denial as unappealable. Right: Check whether the gap is a documentation gap (records exist but were not attached) vs. a clinical gap (criteria genuinely not met). A documentation gap is PEND or OVERTURN; a clinical gap is ADVISE.
Wrong: Drafting a strong overturn letter when the clinical criteria are genuinely not met. Right: Use ADVISE posture — explain the weakness to the reviewer. Never manufacture arguments or misrepresent the clinical record to strengthen a weak appeal.
Wrong: Ignoring the appeal filing deadline. Right: Always surface the deadline from the denial letter. If fewer than 14 days remain, flag the letter as URGENT and recommend submitting within 24–48 hours.
Wrong: Using generic language such as "please reconsider this claim" without addressing the specific denial reason. Right: Quote the CARC code and the payer's stated rationale verbatim, then refute or address each point directly with clinical evidence or documentation.
Wrong: Citing a society guideline without specifying the exact organization, document title, and year. Right: Name the precise source (e.g., "NCCN Clinical Practice Guidelines in Oncology — Non-Small Cell Lung Cancer, v3.2024"). If the exact document cannot be confirmed, bracket it as [Verify: source + year] rather than asserting it as fact.
Wrong: Defaulting to OVERTURN when the clinical criteria are ambiguous or genuinely in doubt. Right: Assess honestly — if there is real uncertainty whether criteria are met, use ADVISE and state the realistic probability of overturn and the compliance risk of overstating the case.
Wrong: Treating Medicare LCD criteria as static facts. Right: Always instruct the reviewer to verify the current LCD version in the CMS Medicare Coverage Database before submitting — criteria are revised periodically and an outdated citation undermines the appeal.
Wrong: Fabricating clinical dates, procedure details, or policy citations not in the user-supplied input. Right: If a fact is not in the input, flag it as [needed from reviewer] — never invent supporting details to strengthen the letter.
Wrong: Bundling multiple denial reasons into one vague appeal paragraph. Right: Address each CARC code separately with its own argument and supporting evidence — reviewers evaluate each denial reason independently.

Quick Reference: CARC → Posture Map

CARC	Description	Default Posture
CO-4	Authorization required	PEND or OVERTURN (if auth exists)
CO-11	Diagnosis inconsistent with procedure	PEND (correct claim)
CO-15	Authorization number invalid	PEND (obtain correct auth number)
CO-16	Claim lacks information	PEND (resubmit with missing info)
CO-29	Timely filing expired	OVERTURN (if proof of timely filing exists) or ACCEPT
CO-50	Non-covered / not medically necessary	OVERTURN or ADVISE
CO-56	Not medically necessary	OVERTURN or ADVISE
CO-57	Denied: not consistent with payer guidelines	OVERTURN or ADVISE
CO-96	Non-covered charge	ACCEPT (or argue misclassification)
CO-97	Bundled / included in another service	PEND (correct coding)
CO-197	Precertification absent	PEND (retroactive auth) or ADVISE
CO-252	Additional documentation requested	PEND (submit documentation)
PR-204	Service not covered by plan	ACCEPT (patient financial counseling)