Every carrier has its own playbook.
We track denial patterns, appeal-window quirks, and procedural leverage points for every major U.S. health insurer. Pick yours below or send your denial and we'll tell you which path fits.
UnitedHealthcare
UnitedHealthcare is the largest U.S. health insurer by membership and runs commercial, Medicare Advantage, and Medicaid plans. Denial volume is correspondingly high, but so is the reversal rate when appeals are filed correctly.
Aetna (CVS Health)
Aetna, owned by CVS Health since 2018, runs commercial group plans, Medicare Advantage, and a large pharmacy benefit footprint via Caremark. GLP-1, specialty drug, and behavioral health denials are the highest-volume categories.
Cigna (Evernorth)
Cigna serves a large employer-sponsored book and runs Medicare Advantage in select markets. The company's automated 'PXDX' review process for high-volume denials has been the subject of recent litigation and regulatory scrutiny.
Anthem / BlueCross BlueShield
BlueCross BlueShield is a federation of 33 independent licensees plus Anthem's nine-state plan group. Each plan has its own denial language, but appeal rights are federally standardized for ACA-compliant products.
Humana
Humana is among the top three Medicare Advantage carriers and also operates Tricare and a smaller commercial book. Medicare Advantage prior auth is the highest-volume denial category.
Medicare (Original + Advantage)
Medicare is a federal program with two delivery modes — Original (fee-for-service Part A/B + Part D drug plans) and Advantage (private MA-C plans). Each has its own appeal ladder, and rights are stronger than most beneficiaries realize.
Kaiser Permanente
Kaiser Permanente is a vertically integrated system — the insurer (Kaiser Foundation Health Plan), medical groups, and hospitals operate as one closed network. Because the treating physician and the plan share an employer, the appeal pathway looks different from a typical PPO denial: the dispute is often with the in-house utilization-review decision rather than with a separate carrier.
Centene / Ambetter
Centene operates one of the largest Medicaid footprints in the U.S. and sells ACA marketplace coverage under the Ambetter brand. Marketplace plans drew elevated regulator and journalist scrutiny in 2024 for higher-than-average denial rates on in-network claims, and Centene-managed Medicaid lines vary plan-by-plan by state.
Molina Healthcare
Molina Healthcare is concentrated in Medicaid managed care, with smaller marketplace and Medicare Advantage footprints. Appeal pathways depend heavily on the underlying line of business and the state Medicaid agency that contracts with Molina.
BCBS Federal Employee Program (FEP)
The BCBS Federal Employee Program is the largest carrier in the Federal Employees Health Benefits (FEHB) program. Because FEHB is regulated by the U.S. Office of Personnel Management (OPM), the appeal process bypasses state insurance departments and ends with OPM rather than a state IRO.
CVS Caremark
CVS Caremark is one of the three largest pharmacy benefit managers in the U.S., administering drug coverage for commercial, Medicare Part D, and Medicaid plans. Caremark denials are issued at the pharmacy benefit layer — separate from the medical benefit — and have their own appeal track.
OptumRx
OptumRx is UnitedHealth Group's pharmacy benefit manager and administers drug coverage for UHC commercial and Medicare Part D plans, plus many third-party employer groups. The appeal track mirrors UHC procedurally but is filed and decided separately from the medical benefit.
TRICARE
TRICARE is the U.S. Department of Defense health program covering active-duty servicemembers, retirees, and eligible family members. Appeals are governed by 32 CFR Part 199, administered by regional contractors (Humana Military and TriWest), with final review by the Defense Health Agency (DHA).
WellCare (Centene)
WellCare is Centene's Medicare Advantage and Part D brand, with a large footprint in MA-PD and standalone Part D plans. Because WellCare operates under Medicare, appeals follow the federal 5-level Medicare Advantage and Part D appeal ladders rather than state external-review programs.