External Review Process for Denied Claims

When a health insurance claim is denied and an internal appeal fails to reverse the decision, federal and state law provide a second line of recourse: external review by an independent organization that has no financial relationship with the insurer. This process applies to most private health plans and was significantly standardized by the Affordable Care Act, which established minimum external review requirements across all states. Understanding how external review works, when it applies, and what outcomes it can produce is essential for anyone navigating a disputed coverage decision.

Definition and scope

External review is a formal process through which an Independent Review Organization (IRO) — a body accredited by the Utilization Review Accreditation Commission (URAC) or a similar entity — evaluates a health insurer's adverse benefit determination and issues a binding decision. Under 45 CFR § 147.136, non-grandfathered health plans subject to the Affordable Care Act must comply with either a state external review process or the federal external review process administered by the Department of Health and Human Services (HHS).

The scope of external review covers adverse benefit determinations, including:

• Denial of a claim as not medically necessary
• Denial based on experimental or investigational treatment classification
• Rescission of coverage
• Denial of urgent care requests in certain circumstances

Plans governed by the Employee Retirement Income Security Act (ERISA) that are self-funded follow a separate pathway under the federal process rather than state law. For a broader understanding of how employer-sponsored plan regulation intersects with these rights, the page on ERISA and employer plan regulation provides detailed context on which plans fall under federal versus state jurisdiction.

How it works

The external review process follows a defined sequence. The numbered steps below reflect the federal minimum standard, which states may exceed but not undercut (HHS External Review Guidance, 2011):

1. Exhaust internal appeals. A claimant must first complete the plan's internal appeals process, or the plan must have waived that requirement.
2. File an external review request. The request must be submitted within four months of receiving the final internal denial notice (the ACA minimum standard).
3. Preliminary review by the plan. The insurer has five business days to determine whether the request is complete and eligible for external review.
4. Assignment to an accredited IRO. The IRO is selected in a manner designed to prevent conflicts of interest — typically through a random or rotating assignment system.
5. IRO review period. The IRO has up to 45 days to issue a decision in a standard review. For expedited review (available when the standard timeline could seriously jeopardize health or the ability to regain maximum function), the IRO must respond within 72 hours.
6. Binding decision. The IRO's decision is binding on the insurer. If the IRO overturns the denial, the plan must cover the service or item.

The National Health Insurance Authority maintains reference material on consumer rights within this framework, including how the external review process interacts with other appeal mechanisms.

Plans that offer HMO-based coverage present specific procedural challenges because the combination of network restrictions and prior authorization requirements generates a distinct category of denial. The HMO Authority reference site covers how HMO plan structures affect claim decisions and what members in closed-network plans need to know about their appeal rights, including the external review pathway.

Common scenarios

External review requests most frequently arise from four dispute categories:

Medical necessity denials. A plan determines that a requested procedure, hospital stay, or treatment does not meet its internal clinical criteria. IROs evaluate these cases against current peer-reviewed medical literature and specialist standards rather than the plan's proprietary criteria.

Experimental or investigational treatment. Insurers deny coverage for treatments classified as not yet proven effective. This category accounts for a significant share of contested external reviews, particularly for cancer treatments and rare disease therapies.

Urgent or emergency care disputes. Disagreements about whether a service qualified as emergency care — relevant under the No Surprises Act and pre-authorization rules — can trigger expedited external review. The page on the No Surprises Act explained details how federal billing protections intersect with this area.

EPO network denials. Exclusive Provider Organization plans cover zero out-of-network care except in emergencies, making network-based denials a common source of disputes. The EPO Authority resource site examines EPO plan mechanics in depth, including the scenarios where external review becomes the primary remedy for members whose claims are denied on network-access grounds.

HDHP cost-sharing disputes. High-Deductible Health Plans generate denial disputes when services are applied to the deductible rather than covered outright, or when preventive care classifications are contested. The HDHP Authority reference site addresses these coverage structure issues and how they interact with HSA-paired plan rules.

Decision boundaries

External review has firm limits that define when it applies and what it can accomplish.

What IROs can decide: IROs can reverse adverse benefit determinations on medical necessity, experimental classification, and coverage eligibility grounds. They cannot rewrite plan terms, award damages, or adjudicate provider billing disputes.

What falls outside external review: Eligibility disputes (whether a person qualifies for the plan at all), claims that the plan's benefit design itself is unlawful, and contractual fee disputes between providers and insurers are not resolved through external review. Those matters route to state insurance regulators or courts.

Grandfathered plans: Health plans that held grandfathered status under the ACA are not required to comply with federal external review standards, though they may still be subject to state-level requirements.

Self-funded ERISA plans: These plans follow the federal external review process only to the extent HHS has determined the state process does not apply. Because ERISA preempts most state insurance laws, self-funded plan members in states without a conforming federal process must use the federal pathway.

The page on how to appeal a claim denial provides the internal appeals framework that must precede any external review request, and your rights as a health insurance consumer covers the full spectrum of federal and state protections that bracket the external review system.

References

• 45 CFR § 147.136 — External Appeals Standards, Electronic Code of Federal Regulations
• CMS External Review Guidance (2011), Centers for Medicare & Medicaid Services
• U.S. Department of Labor — Claims and Appeals (ERISA plans)
• Utilization Review Accreditation Commission (URAC)
• HHS — ACA Implementation FAQs on External Review

The law belongs to the people. Georgia v. Public.Resource.Org, 590 U.S. (2020)