What is external review?
Independent external review means an outside expert—not your insurance company—reviews a denial of medically necessary care (or certain other clinical disputes) and issues a decision that is generally binding on the carrier (C.R.S. § 10-16-113.5).
Colorado's Division of Insurance (DOI) assigns an approved independent external review entity to conduct the review. This is usually not the first step—complete internal appeals first unless an exception applies.
Start with Colorado internal appeals. Background: Appeals roadmap.
When you can use it
External review commonly covers disputes about:
- Medical necessity
- Whether care was appropriate (setting, level of care)
- Experimental or investigational treatment (in qualifying cases)
- Some emergency-care payment denials
It is usually not the right tool for simple billing errors or eligibility paperwork—see Denial decoder.
You can generally request external review when:
- Internal appeal (first level, and voluntary second level if you used it) ended in denial, or
- The carrier missed required internal review deadlines, or
- You qualify for expedited external review (see below)
File within four months after notification of internal appeal denial (C.R.S. § 10-16-113.5(7)). If you completed a voluntary second-level appeal, DOI guidance also references a 60-day window from that denial—follow your denial letter.
How to request it (step by step)
- Read your internal appeal denial. It must tell you about independent external review (C.R.S. § 10-16-113.5(6)).
- Gather documents: denial letters, medical records, clinician support letter.
- Send a written request to your carrier asking for external review (DOI process usually starts with the insurer forwarding the case). Include why you disagree and any new evidence.
- DOI assigns an independent review entity(often within about 2 business days of the carrier's submission per regulation).
- Receive the decision. If the reviewer overturns the denial, the carrier must generally provide the covered service (DOI consumer guide (PDF)).
Questions: Colorado Division of Insurance 303-894-7490 or 1-800-883-2800 · doi.colorado.gov — consumer insurance.
Statute and rules: C.R.S. § 10-16-113.5; 3 CCR 702-4-2-21-8 (standard external review).
How long it takes
- Standard external review: decision within 45 calendar days after the review entity receives the request (C.R.S. § 10-16-113.5(8))
- Expedited external review: as fast as possible, no later than 72 hours after receipt; written confirmation within 48 hours if the initial notice was oral
You may have about 5 business days after assignment to send additional information to the review entity (3 CCR 702-4-2-21-8).
When it does not apply
- Self-funded ERISA employer plans — federal process
- Medicare / Medicare Advantage — CMS appeals
- Health First Colorado (Medicaid) — managed care plan appeals and Office of Administrative Courts fair hearings (healthfirstcolorado.com — appeals)
- Services your policy never covers (contract exclusions), unless a clinician shows the exclusion may not apply
After external review, see Regulator complaints if the carrier does not comply.
Urgent cases
Tell the carrier if you need expedited external review. Colorado law allows expedited external review at the same time as an expedited internal appeal in some situations (C.R.S. § 10-16-113.5(7)).
Your treating provider should explain why waiting for a standard timeline would seriously jeopardize life, health, or ability to regain function.
For urgent prior authorization, see Colorado prior authorization law and expedited appeals.