Every appeal guide, in one place
Counterclaim publishes plain-English appeal guides organised by insurer, state, condition, treatment type, and denial code. Use the navigation below to jump to the section that matches your situation, or scroll to skim the full library.
Need a definition? See the glossary of insurance and appeal terms. Need to file a complaint? Use the 50-state commissioner directory. Need a complete code list? See the full denial-code lookup.
By insurer(11)
Insurer-specific appeal guides covering each carrier's appeals address, internal review levels, common denial patterns, and how to escalate to external review.
UnitedHealthcare
How to appeal a UnitedHealthcare denial: appeals address, internal review levels, common denial reasons, and external review path.
Open guideAnthem
How to appeal a Anthem denial: appeals address, internal review levels, common denial reasons, and external review path.
Open guideAetna
How to appeal a Aetna denial: appeals address, internal review levels, common denial reasons, and external review path.
Open guideCigna
How to appeal a Cigna denial: appeals address, internal review levels, common denial reasons, and external review path.
Open guideHumana
How to appeal a Humana denial: appeals address, internal review levels, common denial reasons, and external review path.
Open guideKaiser Permanente
How to appeal a Kaiser Permanente denial: appeals address, internal review levels, common denial reasons, and external review path.
Open guideBlue Cross Blue Shield
How to appeal a Blue Cross Blue Shield denial: appeals address, internal review levels, common denial reasons, and external review path.
Open guideCentene
How to appeal a Centene denial: appeals address, internal review levels, common denial reasons, and external review path.
Open guideMolina
How to appeal a Molina denial: appeals address, internal review levels, common denial reasons, and external review path.
Open guideMedicare
How to appeal a Medicare denial: appeals address, internal review levels, common denial reasons, and external review path.
Open guideMedicaid
How to appeal a Medicaid denial: appeals address, internal review levels, common denial reasons, and external review path.
Open guide
By state(7)
State-specific appeal guides citing the right statute, the right regulator (DMHC vs CDI in California, TDI in Texas, DFS in New York, and so on), and the state's external review program.
California
California Department of Managed Health Care (DMHC): external review program, statute citations, internal-appeal deadlines, and how to file with the state regulator.
Open guideTexas
Texas Department of Insurance (TDI): external review program, statute citations, internal-appeal deadlines, and how to file with the state regulator.
Open guideFlorida
Florida Office of Insurance Regulation (OIR): external review program, statute citations, internal-appeal deadlines, and how to file with the state regulator.
Open guideNew York
New York Department of Financial Services (DFS): external review program, statute citations, internal-appeal deadlines, and how to file with the state regulator.
Open guidePennsylvania
Pennsylvania Insurance Department (PID): external review program, statute citations, internal-appeal deadlines, and how to file with the state regulator.
Open guideIllinois
Illinois Department of Insurance (IDOI): external review program, statute citations, internal-appeal deadlines, and how to file with the state regulator.
Open guideOhio
Ohio Department of Insurance (ODI): external review program, statute citations, internal-appeal deadlines, and how to file with the state regulator.
Open guide
By condition(6)
Condition-specific guides for the diagnoses that generate the most denials in the US: cancer, mental health, diabetes, autism, infertility, weight-loss treatment, transplants, and rare disease.
Cancer treatment denials
Chemotherapy, immunotherapy, off-label oncology drugs, NCCN-guideline appeals.
Open guideMental health & SUD denials
Therapy, residential, IOP/PHP - parity arguments under MHPAEA.
Open guideAutism / ABA therapy denials
State autism mandates, ABA hour caps, age limits.
Open guideInfertility / IVF denials
State IVF mandates, cycle limits, age cutoffs.
Open guideWeight-loss / GLP-1 denials
Bariatric surgery, semaglutide, tirzepatide coverage rules.
Open guideOrgan transplant denials
Listing denials, post-transplant immunosuppressants, donor coverage.
Open guide
By treatment type(6)
Treatment-specific guides organised by what was denied: imaging, physical therapy, surgery, durable medical equipment, specialty drugs, genetic testing, skilled nursing, and home health.
Physical therapy
Visit caps, medical necessity reviews, plateau letters.
Open guideDurable medical equipment
Wheelchairs, CPAP, prosthetics, orthotics, mobility aids.
Open guideSpecialty drugs / biologics
Tier 4-5 drugs, formulary exceptions, step therapy bypass.
Open guideSkilled nursing facility
Post-acute SNF stays, custodial-vs-skilled determinations.
Open guideHome health care
Homebound criteria, intermittent vs continuous care.
Open guideOut-of-network emergency care
No Surprises Act protections, prudent layperson standard, balance billing.
Open guide
Deep-dive guides(9)
Topical guides that explain a single appeal mechanism (internal vs external review, ERISA rights, parity, the No Surprises Act) end to end with sample language and citations.
Letter of medical necessity playbook
Exactly what your physician should write, and the citations to include.
Open guideMental Health Parity (MHPAEA) for patients
How to spot a parity violation and force the comparative analysis.
Open guideERISA appeal rights
What self-funded plan members can demand under federal law.
Open guideState external review programs
How IMR / IRO / IHCAP work in every state, side by side.
Open guideExpedited / urgent appeals
72-hour timelines, what to put in the doctor's urgency letter.
Open guideInsurance commissioner complaints
When and how to escalate to your state regulator for enforcement.
Open guidePeer-to-peer review
How your physician can call the insurer's medical director directly.
Open guideSample appeal letters
Real letter templates for the most common denial types.
Open guideMedicare denial appeals
The five appeal levels, Jimmo maintenance coverage, observation status, and the SNF 3-day rule.
Open guide
Denial codes A-Z(23)
Direct links to every denial-code appeal guide, sorted alphabetically by code. For the larger lookup of 30+ codes (including those without a deep guide) see the master code list.
- CO-109 Wrong Payer Denial (CO-109)
- CO-11 Prior Authorization Denial (CO-11)
- CO-119 Benefit Maximum Reached Denial (CO-119)
- CO-16 Missing Information Denial (CO-16)
- CO-167 Diagnosis Not Covered Denial (CO-167)
- CO-18 Duplicate Claim Denial (CO-18)
- CO-204 Service Not Covered Denial (CO-204)
- CO-22 Covered by Another Payer Denial (CO-22)
- CO-242 Referral Required Denial (CO-242)
- CO-27 Coverage Terminated Denial (CO-27)
- CO-31 Patient Not Identified Denial (CO-31)
- CO-4 Modifier Error Denial (CO-4)
- CO-45 Exceeds Fee Schedule Denial (CO-45)
- CO-50 Medical Necessity Denial (CO-50)
- CO-55 Experimental Treatment Denial (CO-55)
- CO-96 Non-Covered Charge Denial (CO-96)
- CO-97 Out-of-Network Provider Denial (CO-97)
- MHPAEA Mental Health Parity Denial (MHPAEA)
- NSA Balance Billing Denial (No Surprises Act)
- PR-1 Deductible Not Met Denial (PR-1)
- PR-27 Filing Deadline Denial (PR-27)
- PR-49 Preventive Service Denial (PR-49)
- PR-50 Step Therapy Denial (PR-50)
Looking for a code that is not listed? See the full 30+ denial-code master lookup.
Reference pages(5)
Reference material that complements the per-insurer and per-state guides.
Glossary of insurance terms
Plain-English definitions of 60+ terms: deductible, ERISA, MHPAEA, prior authorization, fee schedule, IRO, and many more.
Open guideState insurance commissioners
Hotline, complaint URL, and email for every US state and DC insurance department.
Open guideMaster denial-code lookup
30+ X12 / CARC denial codes with short descriptions and links to detailed appeal guides where available.
Open guideHow Counterclaim works
The 5-agent AI pipeline that drafts your appeal in under a minute.
Open guideInsurance appeal FAQ
Detailed answers to every common question about deadlines, success rates, and external review.
Open guideCounterclaim vs traditional advocates
How AI-drafted appeals compare to hiring a billing advocate or attorney.
Open guide
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