How ACA claim appeals are structured

What the ACA requires after a denial

Under the Affordable Care Act (ACA), individual and employer group health plans, including marketplace plans, employer coverage, and Medicare Advantage, must follow a standardized appeals process after a claim denial. The right to appeal is statutory; the stages below summarize the process rules and the related CMS data fields, not a case-specific recommendation.

Stage 1: What the denial notice must contain

Plan rules require a written Explanation of Benefits (EOB) or denial notice that states the specific reason for denial, references the plan provisions or criteria used, explains how to appeal and by when, and notes the right to request the clinical criteria applied. Common coded reasons in the notices include "not medically necessary," "experimental/investigational," "out-of-network," "missing documentation," or "service not covered."

Stage 2: Documentation the appeals record typically includes

Internal-appeal files commonly include the EOB showing the denial, medical records supporting the treatment, a treating-physician letter of medical necessity, peer-reviewed literature when the denial cites experimental status, the plan's Summary of Benefits and Coverage (SBC) and Evidence of Coverage (EOC), and any prior authorization for the same or related services.

Stage 3: Internal appeal (first required tier)

The first required tier is an internal appeal filed with the plan. For ACA marketplace plans the window is usually 180 days from the denial notice. Response clocks are typically 30 days for pre-service denials, 60 days for post-service claims, and 72 hours for urgent care. Expedited review is available when the plan's own criteria treat the case as urgent; the plan must then respond within 72 hours.

Stage 4: Peer-to-peer clinical review

Plan documents describe a peer-to-peer review as a discussion between the treating physician and the plan's medical reviewer about the denial rationale. It can occur before or during the internal appeal. CMS and industry reporting treat this stage as one where a large share of contested denials are reversed without full external escalation.

Stage 5: External review (Independent Review Organization)

After an internal appeal is denied, ACA rules provide for external review by an Independent Review Organization (IRO) independent of the insurer; the IRO decision is legally binding. The filing window is usually about four months after internal-appeal denial; consumer cost is typically $0–$25; IRO clocks are 45 days (standard) or 72 hours (expedited). Medicare Advantage uses a Qualified Independent Contractor (QIC) review, then an Administrative Law Judge hearing path.

Stage 6: State insurance department complaint channel

State insurance commissioners accept consumer complaints that create a regulatory record and can trigger a market-conduct review independent of the plan's appeals path. Commissioner contacts for each state are listed in the state directory. Complaint volume by carrier also feeds the NAIC complaint ratios shown on insurer profiles.

Adjacent assistance channels (not PlainInsurer services)

Outside the statutory plan path, disease-specific nonprofits and ACA-funded state consumer-assistance programs publish appeals help in many states. Employer HR may participate when coverage is group-based. Large-claim disputes sometimes involve ERISA or insurance counsel; those are separate professional channels, not services PlainInsurer provides.

How CMS appeals columns describe insurer behavior

The CMS Transparency in Coverage public-use files include claim-denial rates, appeal-filing rates, and appeal-overturn rates. Reading the three columns together turns a single denial-rate snapshot into a fuller picture. An issuer can show a high denial rate with a high overturn rate (aggressive initial adjudication corrected on appeal) or a moderate denial rate with a very low overturn rate (denials that are administratively harder to reverse). Among issuer-state rows, appeal-overturn rates vary from under 5% to over 50%. A high overturn rate with a low appeals-filed rate is consistent with many denials never entering the formal appeals path.

What initial denials look like in the data

Initial denials are common in the CMS files, and a substantial share of contested denials are reversed later in the path. The same issuer-state row that reports how often a plan denies claims also reports how often those denials are overturned on appeal, which is the quantitative way to separate high-friction adjudication from permanently upheld denials.