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External Review9 min read·Last reviewed: May 18, 2026

External Review by IRO: The Binding Second Opinion Most Patients Skip

After internal appeals are upheld, external review by an Independent Review Organization (IRO) is the binding second opinion. Free under federal law. 30-50% reversal rate. The federal process under 45 CFR §147.136(d), every state's variant, and when expedited 72-hour review applies.

By Apellica Editorial Team · Reviewed against CMS, DOL, and NAIC published guidance
Quick answer (60 seconds)

External review is the second-opinion lane after internal appeals are upheld. An Independent Review Organization (IRO) — a physician panel independent of the carrier — reviews and issues a decision binding on the carrier. Free to the patient under 45 CFR §147.136. Standard: 45 days (federal) / 30 days (most states). Expedited urgent: 72 hours. Reversal rates run 30-50%. Most patients never use external review because the carrier's 'internal appeal upheld' letter doesn't explain it well.

External review is available for adverse benefit determinations involving medical necessity, experimental/investigational treatment, rescission, and (in some states) comparability of services. NOT available for administrative/eligibility disputes, billing/coding errors, premium disputes, or claims that haven't completed internal appeals (with limited exceptions).

Three IRO tracks

Track A — State external review: for fully-insured plans, administered by state DOI or specialized agency (California DMHC). Track B — Federal external review for ERISA self-funded plans: under 29 CFR §2590.715-2719 and 45 CFR §147.136(d); HHS-OPM-accredited IROs randomly assigned. Track C — Medicare Advantage IRE (Maximus): Level 2 Independent Review Entity.

How the federal external review process works

Step 1 — Preliminary review: within 5 business days of request, plan determines eligibility. Step 2 — IRO assignment: plan assigns to accredited IROs on rotational basis (no shopping for friendly IROs). Step 3 — Document submission: 10 business days to submit additional documentation. Step 4 — IRO decision: 45 days standard / 72 hours expedited. Step 5 — Decision is binding: carrier must comply if IRO reverses.

State external review variations

StateProgram nameNotable feature
CaliforniaIndependent Medical Review (IMR) via DMHCFree; binding; covers most fully-insured + Medi-Cal MC
TexasIRO Review via TDICarrier must contract with IRO from TDI's list
New YorkExternal Appeal via DFS$50 filing fee (waived for hardship)
FloridaSubscriber Assistance Program via OIRState-administered
MassachusettsOffice of Patient Protection (DOI)Covers fully-insured + self-insured if employer opts in

Building the external review packet

The IRO works from a written record (rarely conducts hearings). Required elements: external review request form, all denial letters and appeal correspondence, complete medical record, Letter of Medical Necessity (enormous weight at IRO — physician panels), professional society guidelines, peer-reviewed literature for EI disputes, case summary written to a physician audience.

The case summary lets the IRO physician get oriented fast — patient demographics in 2-3 sentences, service in dispute, carrier's rationale, clinical argument for reversal, relief requested, key exhibits.

Frequently asked questions

Is external review really free?

For federal external review under ACA-governed plans: yes. The carrier bears the IRO fee. For state programs: usually free; a few states (NY) charge a small fee waived for hardship.

How long do I have to file external review?

4 months (120 days) from the final internal adverse determination under federal rules. Some states differ — always check the final denial letter.

Is the IRO decision really binding?

Yes — on the carrier. The carrier must comply. Patient retains right to litigate further (ERISA or state law) but rarely does after IRO. The binding-on-carrier status is what makes external review the most powerful lever in the appeals system.

Who picks the IRO?

Plan/carrier does NOT pick. Federal law requires rotational/random assignment. State programs use IROs accredited and selected by state DOI. Independence safeguard.

What if the carrier won't process my external review request?

File complaint with state DOI (fully-insured) or DOL EBSA (ERISA), and directly contact federal external review administrator. Refusing to comply is itself a regulatory violation.

Can I appeal the IRO decision?

IRO decision binds the carrier and is the end of the administrative path. To challenge, file civil litigation (ERISA §502 for self-funded; state court for fully-insured). Courts give substantial weight to IRO decisions.

Sources

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