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Denial Code Lookup

Understand a denial code

CO-16Claim/Line Denial

Claim/service lacks information needed for adjudication.

Common Cause

Missing or invalid data element on the claim.

Recommended Action

Review remark codes for the specific missing element and resubmit with corrected data.

CO-45Contractual Adjustment

Charge exceeds fee schedule/maximum allowable amount.

Common Cause

Billed amount above the contracted allowable.

Recommended Action

Verify fee schedule alignment; typically not appealable if contract terms are current.

CO-97Bundling

Benefit for this service is included in the payment for another service already adjudicated.

Common Cause

Service considered bundled under NCCI or payer-specific edits.

Recommended Action

Confirm modifier appropriateness; appeal with documentation if unbundling is clinically supported.

CO-50Medical Necessity

Non-covered service because it is not deemed a medical necessity.

Common Cause

Diagnosis does not support medical necessity per payer policy (LCD/NCD).

Recommended Action

Review policy criteria; submit supporting documentation or corrected diagnosis if applicable.

CO-29Timely Filing

The time limit for filing has expired.

Common Cause

Claim submitted after the payer's timely filing deadline.

Recommended Action

Verify submission date evidence; appeal only if a documented exception applies.

PR-1Patient Responsibility

Deductible amount.

Common Cause

Patient has not met annual deductible.

Recommended Action

Route balance to patient billing; confirm deductible accumulator accuracy if disputed.

PR-2Patient Responsibility

Coinsurance amount.

Common Cause

Standard plan cost-share applied post-adjudication.

Recommended Action

Route to patient billing per standard statement cycle.

CO-18Duplicate

Exact duplicate claim/service.

Common Cause

Claim previously submitted and adjudicated.

Recommended Action

Confirm original claim status before resubmitting or appealing.

CO-109Coordination of Benefits

Claim/service not covered by this payer/contractor.

Common Cause

Incorrect payer sequencing or COB information.

Recommended Action

Verify primary/secondary payer order and resubmit to correct payer.

CO-197Authorization

Precertification/authorization/notification absent.

Common Cause

Required prior authorization was not obtained or documented.

Recommended Action

Confirm authorization was secured; appeal with authorization reference if available.

Code	Group	Description	Common Cause	Recommended Action
CO-16	Claim/Line Denial	Claim/service lacks information needed for adjudication.	Missing or invalid data element on the claim.	Review remark codes for the specific missing element and resubmit with corrected data.
CO-45	Contractual Adjustment	Charge exceeds fee schedule/maximum allowable amount.	Billed amount above the contracted allowable.	Verify fee schedule alignment; typically not appealable if contract terms are current.
CO-97	Bundling	Benefit for this service is included in the payment for another service already adjudicated.	Service considered bundled under NCCI or payer-specific edits.	Confirm modifier appropriateness; appeal with documentation if unbundling is clinically supported.
CO-50	Medical Necessity	Non-covered service because it is not deemed a medical necessity.	Diagnosis does not support medical necessity per payer policy (LCD/NCD).	Review policy criteria; submit supporting documentation or corrected diagnosis if applicable.
CO-29	Timely Filing	The time limit for filing has expired.	Claim submitted after the payer's timely filing deadline.	Verify submission date evidence; appeal only if a documented exception applies.
PR-1	Patient Responsibility	Deductible amount.	Patient has not met annual deductible.	Route balance to patient billing; confirm deductible accumulator accuracy if disputed.
PR-2	Patient Responsibility	Coinsurance amount.	Standard plan cost-share applied post-adjudication.	Route to patient billing per standard statement cycle.
CO-18	Duplicate	Exact duplicate claim/service.	Claim previously submitted and adjudicated.	Confirm original claim status before resubmitting or appealing.
CO-109	Coordination of Benefits	Claim/service not covered by this payer/contractor.	Incorrect payer sequencing or COB information.	Verify primary/secondary payer order and resubmit to correct payer.
CO-197	Authorization	Precertification/authorization/notification absent.	Required prior authorization was not obtained or documented.	Confirm authorization was secured; appeal with authorization reference if available.

RCM Glossary

Revenue cycle terminology

A/R Days: The average number of days it takes an organization to collect payment after a claim is submitted.
Clean Claim: A claim submitted without errors that processes successfully through payer adjudication on the first attempt.
CARC: Claim Adjustment Reason Code — a standardized code explaining why a claim or service line was adjusted or denied.
RARC: Remittance Advice Remark Code — supplemental codes providing additional explanation alongside a CARC.
Clearinghouse: An intermediary that transmits claims electronically between providers and payers, validating formatting before submission.
Coordination of Benefits (COB): The process of determining the order in which multiple insurance plans pay for a claim.
Credentialing: The process of verifying a provider's qualifications and enrolling them with payers to bill for services.
Denial Rate: The percentage of submitted claims that are denied by payers on first submission.
EOB: Explanation of Benefits — a statement from a payer detailing how a claim was processed.
ERA: Electronic Remittance Advice — the electronic version of payment and adjustment details from a payer.
Global Period: The defined timeframe following a surgical procedure during which related follow-up care is bundled into the original payment.
Net Collection Rate: The percentage of collectible revenue actually collected, after contractual adjustments.
NCCI Edits: National Correct Coding Initiative edits that prevent improper payment for code combinations that should not be billed together.
Prior Authorization: Payer approval required before certain services are rendered in order for the claim to be reimbursed.
Revenue Cycle Management (RCM): The end-to-end financial process that healthcare organizations use to track revenue from patient registration to final payment.
Timely Filing Limit: The maximum number of days after service in which a claim must be submitted to a payer to be considered for payment.