Medical Billing in Colorado: Payer Landscape, Medicaid & Timely Filing

Colorado Medicaid runs a Regional Accountable Entity (RAE) model — 5 regions managing physical, behavioral, and long-term care under one administrative umbrella. Commercial payers include Anthem, Cigna, and Aetna. Timely filing is 180 days for most payers. The Denver metro and rural mountain counties have very different payer mixes and authorization burdens.

3CO Medicaid Plans
365 daysMedicaid Filing Limit
11.6%Natl. Avg Denial Rate
95%+Clean Claim Target
Medical Billing in Colorado: The Short Version

Colorado structures Medicaid differently than most states: instead of full-risk MCOs, Health First Colorado uses Regional Accountable Entities (RAEs) that coordinate care while most physical health claims pay fee-for-service through the state — with behavioral health capitated through the RAEs. Kaiser Permanente's large closed-network presence and a strong state exchange (Connect for Health Colorado) round out a distinctive market.

Major Payers in Colorado

PayerTypeWhat Billing Teams Should Know
Anthem BCBS of ColoradoCommercial / Blue planLargest commercial payer
UnitedHealthcareCommercial / MADenver metro employer book; owns Rocky Mountain Health Plans
Kaiser Permanente ColoradoIntegrated HMOMajor Front Range closed-network share
CignaCommercialEmployer self-funded presence
Rocky Mountain Health PlansRegionalWestern Colorado strength; UHC-owned but distinct products
Health First Colorado (HCPF)MedicaidRAE regions; physical health mostly FFS

Health First Colorado: Managed Care Plans

Administered by the Department of Health Care Policy & Financing (HCPF). The patient's plan assignment — not just Medicaid eligibility — determines the portal, prior-auth list, and filing rules that apply.

PlanNotes
Regional Accountable Entities (RAEs)Care coordination + behavioral health capitation by region — physical health largely pays FFS through HCPF
Denver Health Medicaid ChoiceOne of two true managed care plans
Rocky Mountain Health Plans PrimeWestern-slope managed care option

Timely Filing Limits for Colorado Claims

Initial-claim windows for the payers Colorado practices bill most. Commercial limits are contract-specific — always confirm against your provider agreement and the payer's current manual.

PayerTimely Filing LimitNotes
Health First Colorado365 days from date of serviceInterim claims rules apply for some provider types
Medicare (original)12 months from date of serviceSet by federal law; no contract variation
UnitedHealthcare (commercial)90 days from date of serviceContract-specific; some plans allow 180
Aetna (commercial)120 days from date of serviceContract-specific; verify provider agreement
Cigna (commercial)90 days from date of serviceContract-specific; verify provider agreement
Humana (commercial)90 days from date of serviceAmong the strictest; Medicare Advantage differs

Verified against payer publications at time of writing (July 2026). Filing limits change by contract and plan year — treat this table as a starting point, not a substitute for the payer manual. See our methodology.

Colorado Billing Realities to Know

RAE Model ≠ MCO Model — Split Your Workflows

Colorado’s physical health Medicaid mostly runs fee-for-service billed directly to the state, while behavioral health services are capitated through Regional Accountable Entities (RAEs). This means a single patient can require two separate workflows depending on the service rendered. Billing staff must identify the service type first — not just the payer — before routing the claim. Submitting a behavioral health claim to the FFS state system instead of the RAE will result in rejection that is not a timely filing exception.

Behavioral Health RAE Billing — Region Matters

Colorado is divided into seven RAE regions, each administered by a different organization. The RAE that handles the patient’s behavioral health capitation is determined by their county of residence, not the provider’s location. A Denver-area provider seeing a patient from a different county must bill that patient’s assigned RAE, which may be a different organization than the one covering the provider’s own county. Verify the patient’s RAE assignment through the Colorado PEAK portal or the Health First Colorado provider portal before submitting BH claims.

Kaiser Front Range Density

Kaiser Permanente Colorado’s concentration in the Denver-Boulder Front Range corridor means a meaningful share of commercial patients in that market are Kaiser members in a closed-network HMO. Non-participating providers who see Kaiser members out-of-network face strict claim routing rules and limited reimbursement outside emergencies. Practices in the Front Range corridor should have a defined protocol for Kaiser out-of-network encounters — including collecting the member’s Kaiser ID, understanding the emergency versus urgent distinction, and routing claims to Kaiser’s regional claims address rather than a commercial clearinghouse.

Mountain-Resort Out-of-State and Travel Payer Mix

Practices in ski resort communities (Summit County, Eagle County, Pitkin County, and similar) regularly encounter patients insured by out-of-state Blues plans (processed through BlueCard), international travel insurance, and employer plans domiciled in other states. BlueCard claims route through the patient’s home Blue plan, not Colorado’s Anthem/BCBS — verify the Alpha Prefix on the card to route correctly. Travel insurance claims often require pre-certification proof and may demand itemized bills in formats different from standard CMS-1500 workflows.

Frequently Asked Questions

Health First Colorado allows 365 days from date of service for initial claims, administered by the Department of Health Care Policy & Financing (HCPF). Managed care plans operating in Colorado may apply shorter contractual windows, so always verify each plan's provider manual.
Regional Accountable Entities (RAEs), Denver Health Medicaid Choice, Rocky Mountain Health Plans Prime. Each plan maintains its own provider portal, prior authorization list, and claim submission rules — the patient's plan assignment, not just Medicaid status, determines how a claim must be billed.
Anthem BCBS of Colorado, UnitedHealthcare, Kaiser Permanente Colorado, Cigna, Rocky Mountain Health Plans, alongside Medicare and Health First Colorado. See the payer landscape table on this page for what billing teams should know about each.
Colorado uses Regional Accountable Entities (RAEs) rather than full-risk MCOs. RAEs coordinate care and hold capitation for behavioral health, but most physical health claims still pay fee-for-service through HCPF. Practices bill the state for physical health and the RAE’s behavioral health organization for BH services — two parallel workflows.

See How Colorado Practices Compare

Benchmark your denial rate, Days in AR, and clean claim rate against 2026 specialty data.

Common Codes Billed in This State

Frequently billed codes in this state’s payer environment, with notes on state-specific rules and common denial patterns.

Code Description State-Specific Note
99213 Office visit, est. patient — level 3 Billed through one of 5 RAE regions; verify enrollee RAE
99214 Office visit, est. patient — level 4 Anthem, Cigna, and Aetna all require auth above level 4
99215 Office visit, est. patient — level 5 Document high MDM; Cigna audit rate in CO is elevated
Mod. GT Telehealth — real-time audio/video Required for Health First Colorado telehealth claims
H0001 Alcohol/drug assessment High demand in CO behavioral health; verify RAE coverage
CO-50 Non-covered service Common denial when RAE network coverage isn’t confirmed

Codes and reimbursement rates change annually. Verify current fee schedules with each payer before billing. Full code lookup →

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