Medical Billing Time Limits in Colorado: Deadlines and Appeals

Medical billing time limits in Colorado run on two clocks. Out-of-network providers have 180 days after receiving a patient’s insurance information to submit a claim under C.R.S. 12-30-113, and insurers then have 30 calendar days to pay, deny, or settle a clean electronic claim (45 days for paper) under C.R.S. 10-16-106.5. Miss either window and the penalties are automatic: providers lose most of their reimbursement, and insurers owe interest plus a penalty on the claim amount.

How Long Providers Have to File a Claim

The 180-day rule applies specifically to out-of-network providers. File within that window and the reimbursement is the greater of 110 percent of the carrier’s median in-network rate for the same service in the same geographic area, or the 60th percentile of the in-network rate drawn from the state’s all-payer claims database.¹

Miss the 180 days and the reimbursement drops to 125 percent of the Medicare rate for the same service in the same area. That’s a meaningful pay cut for most specialties, and it happens automatically. The provider also cannot bill the patient for the shortfall beyond the patient’s coinsurance, deductible, or copayment, so the loss falls entirely on the provider.¹

In-network providers work off a different clock. Their filing deadline is set by the contract with the insurer, not by a single statewide statute. Many commercial plans set that deadline somewhere between 90 and 180 days from the date of service. Missing a contractual deadline has the same practical effect as missing a statutory one: the insurer can deny payment outright, so each payer contract needs to be read closely.

How Long Insurers Have to Pay

Once a clean claim is in, the clock shifts. Under C.R.S. 10-16-106.5, carriers must pay, deny, or settle a clean claim within 30 calendar days if it was submitted electronically, or 45 calendar days if submitted by other means. A carrier that needs more information has to ask for it in writing within 30 days of receiving the claim. For electronic submissions, receipt has to be acknowledged within one business day, which creates a paper trail if a dispute comes up later.²

Carriers that blow the deadline owe two things on top of the claim itself: interest at 10 percent annually on the amount owed, and a penalty equal to 20 percent of the total claim amount. If a carrier delegates claims processing to a third-party administrator, the carrier still bears the legal obligation. Workers’ compensation claims filed under articles 40 to 47 of title 8 are excluded from the prompt payment rules.²

Medicare and Colorado Medicaid Deadlines

Medicare claims must be filed within one calendar year from the date of service. If the deadline passes, Medicare will not pay its share, and the provider generally cannot bill the patient for the unpaid amount.³

Colorado Medicaid (Health First Colorado) runs on its own windows:

General claims: 365 days from the date of service.
Pharmacy claims: 120 days.
Medicare crossover claims, where Medicare processes first and passes the remainder to Medicaid: 120 days from the Medicare payment or denial date.
Medicare-denied, non-covered, or exhausted benefits that aren’t true crossover claims: 365 days from the date of service or 120 days from the Medicare denial date, whichever is longer.⁴

One point catches providers off guard: waiting on prior authorization or on correspondence from the state is not an acceptable reason for late filing. The Department of Health Care Policy and Financing expects the claim to go in on time even if the initial result is a denial, and then to be worked from there. Phone calls and informal correspondence do not count as proof of timely filing.⁵

Employer Plans Under ERISA

Many Colorado residents get coverage through an employer-sponsored plan governed by the federal Employee Retirement Income Security Act, and ERISA has its own decision timelines that run alongside the state rules. Post-service claims (the most common kind for medical billing) must be decided within 30 days of receipt, with a possible 15-day extension if the plan notifies the participant before the first deadline expires. Pre-service claims get 15 days, also with a possible 15-day extension. Urgent care claims must be decided within 72 hours.⁶

ERISA requires plans to pay approved benefits within a “reasonable time” but does not set a hard payment deadline the way Colorado’s prompt payment statute does. In practice, the 10-percent interest and 20-percent penalty under state law may not reach self-funded ERISA plans that are exempt from state insurance regulation. Providers dealing with those plans usually have to pursue remedies through the federal system rather than state enforcement.

Exceptions and Defenses for Late Filing

Missing a deadline is not always the end of the road. Colorado Medicaid allows claims filed after the standard window if the provider can document a qualifying adverse action, such as specific fiscal agent correspondence identifying the claim, a date-stamped returned claim, a provider enrollment approval letter, or an eligibility backdate notification. When one of those applies, the follow-up submission must arrive within 60 days of the last adverse action.⁵

What Medicaid will not accept as an excuse: billing agent problems, clearinghouse failures, and software issues. Those are treated as the provider’s responsibility to resolve, not valid grounds for late filing.⁵

For commercial insurance, the available defenses are narrower and depend on the insurer’s policies and the provider’s contract. A genuine disruption beyond the provider’s control, like a natural disaster or a system-wide electronic health record failure, may support a late filing exception, but the provider carries the burden of proving the disruption and showing prompt action once it cleared. Good-faith errors, where the claim was submitted on time but with incorrect information, may also be correctable if the provider acts quickly and can document the original timely submission.

Appeals Timelines When a Claim Is Denied

Colorado requires carriers to offer a two-level internal review process for denied claims. C.R.S. 10-16-113 sets the framework, and the carrier has to notify the provider or individual of the right to use it. The specific filing and decision timelines vary by insurer and plan type, so the carrier’s published appeals procedures and any contractual deadlines need to be checked as soon as a denial arrives. Waiting too long to appeal is one of the most common and costly mistakes in medical billing.

If the insurer upholds the denial after internal review, the dispute can go to an independent external review organization under C.R.S. 10-16-113.5. The external reviewer is not affiliated with the insurer.⁷

Disputes arising under the federal No Surprises Act can go through the federal Independent Dispute Resolution process instead. Both parties pay an administrative fee of $115 for 2026 to participate, and an independent arbitrator picks one side’s offer, which pushes both parties toward reasonable numbers. Colorado also runs a Carrier Payment Arbitration Program for out-of-network billing disputes that fall under state jurisdiction.⁸

How Long Providers Can Pursue Old Medical Debt

The general statute of limitations for collecting a liquidated debt in Colorado is six years under C.R.S. 13-80-103.5. For medical debt specifically, the legislature has shortened that period. An amendment to C.R.S. 13-80-101 created a three-year limitation on permissible extraordinary collection actions involving medical debt as defined in C.R.S. 6-20-201. Once the period expires, a provider or collection agency loses the legal right to sue, though the debt itself doesn’t disappear and can continue to affect credit reports for up to seven years.

A partial payment or a written acknowledgment of the debt can restart the limitations clock, which is why making a token payment on old medical debt without understanding the consequences can be a costly move.

1
Justia. Colorado Code 12-30-113 – Billing and Payment Procedures for Covered Services
2
Justia. Colorado Revised Statutes 10-16-106.5 – Prompt Payment of Claims
3
Medicare.gov. Filing a Claim
4
Colorado Department of Health Care Policy & Financing. General Provider Information Manual
5
Colorado Department of Health Care Policy & Financing. Special Provider Bulletin – Claims Submission (B1800413)
6
U.S. Department of Labor. Filing a Claim for Your Health Benefits
7
Justia. Colorado Revised Statutes 10-16-113.5 – External Review
8
Colorado Division of Insurance. Federal No Surprises Act / Colorado Out-of-Network Billing