Behavioral health billing reference
Behavioral Health Denial Code Library
Plain-language explanations for the CARC and RARC denial codes that show up most often on addiction treatment and mental health claims—not a generic payer list. Each entry covers BH-specific root causes, appeal pathways, and prevention tips for RTC, PHP, IOP, detox, and outpatient billing.
15
Codes covered
CARC & RARC
Reference types
Appeal guidance
Included
Showing 15 of 15
- CO-50AppealableMedical Necessity
Medical Necessity Denial
The payer determined the service is not medically necessary under their coverage policy. The allowed amount is reduced to zero and the provider typically cannot bill the patient for the denied service unless a valid ABN or financial agreement exists.
View code guide - CO-197AppealableAuthorization
Precertification / Authorization Absent
The payer denies payment because required precertification, prior authorization, or notification was not obtained—or cannot be matched to the claim—before services were rendered.
View code guide - CO-96AppealableNon-Covered
Non-Covered Charge(s)
The payer considers the service non-covered under the patient's plan. Payment is denied in full unless contractual rules allow patient billing for the specific non-covered benefit.
View code guide - CO-4AppealableCoding Error
Modifier Inconsistent With Procedure
The procedure code is inconsistent with the modifier used, or a required modifier is missing. The payer cannot adjudicate the claim until coding elements align with their edits.
View code guide - CO-16Non-appealableCoding Error
Missing Claim Information
Claim/service lacks information or has submission/billing error(s) which are needed for adjudication. Additional details are required before the payer can process payment.
View code guide - CO-18AppealableDuplicate
Duplicate Claim / Service
The exact same claim or service was previously processed or paid. The payer treats this submission as a duplicate and denies payment on the repeat.
View code guide - CO-22Non-appealableCoordination of Benefits
Coordination of Benefits
This care may be covered by another payer per coordination of benefits (COB). The claim must be processed by the primary plan before the secondary payer considers payment.
View code guide - CO-45Non-appealableContractual Adjustment
Charge Exceeds Fee Schedule
Charge exceeds fee schedule or maximum allowable amount. The payer reduces payment to the contracted or statutory allowed amount; this is often a contractual write-off, not a recoverable denial.
View code guide - PR-96AppealablePatient Responsibility
Non-Covered — Patient Responsibility
Non-covered charge(s) assigned to patient responsibility. The payer will not pay; the provider may bill the patient per plan rules and financial policy.
View code guide - PR-1Non-appealablePatient Responsibility
Deductible Amount
Deductible amount applied to patient responsibility. The payer processed the claim but payment is reduced by the patient's unmet annual deductible.
View code guide - PR-2Non-appealablePatient Responsibility
Coinsurance Amount
Coinsurance amount applied to patient responsibility. The payer paid their percentage; the patient owes the remaining share per plan design.
View code guide - N130AppealablePatient Responsibility
Consult Plan Benefit Documents
Remittance advice remark indicating the payer needs the provider to consult plan benefit documents—or that coverage determination depends on plan language not fully automated on the claim.
View code guide - N286Non-appealableCoding Error
Invalid or Missing Referring Provider
Missing, incomplete, or invalid referring provider primary identifier. The payer cannot validate the referral or ordering provider on the claim—typically the referring physician NPI, name, or enrollment record.
View code guide - N522AppealableDuplicate
Duplicate Crossover Claim
Duplicate of a claim processed, or to be processed, as a crossover claim. The payer received a direct submission while the same claim is already in the crossover pipeline from the primary plan.
View code guide - MA130Non-appealableCoding Error
Incomplete or Invalid Claim Information
Medicare remark: your claim contains incomplete and/or invalid information. Medicare cannot process until missing or incorrect data is corrected.
View code guide
FAQ
Denial Code Questions
What is a denial code on a medical claim?
Denial codes are the standardized adjustment reason codes payers attach to remittances when they reduce or refuse payment. CARCs (Claim Adjustment Reason Codes) explain the high-level reason — for example CO-197 for absent authorization — while RARCs (Remittance Advice Remark Codes) add detail about what to fix. Every behavioral health denial maps to one of these codes, and each has a specific root cause, appeal path, and prevention step.
What are the most common denial codes in behavioral health billing?
The codes behavioral health programs see most are CO-197 (absence of precertification/authorization), CO-16 (claim lacks information needed for adjudication), PR-1/PR-2 (deductible and coinsurance amounts), CO-97 (payment included in another allowance), and medical-necessity denials that surface under various CARC/RARC pairs. Authorization and medical-necessity categories dominate because detox, residential, PHP, and IOP claims all depend on payer approval windows.
How do I appeal a denied behavioral health claim?
Start from the denial code: it tells you whether the fix is a corrected claim, missing documentation, or a formal appeal. Gather the clinical record that supports medical necessity, the authorization history, and the payer's own policy language, then submit within the appeal window on the remittance — typically 90 to 180 days. Cipher's denial library lists the appeal pathway for each code individually.
Can most behavioral health denials be prevented?
Yes. The majority trace to front-end events: verification gaps, missing or expired authorizations, level-of-care mismatches, and documentation that does not meet the payer's medical-necessity standard. Disciplined verification of benefits and daily utilization review prevent most denials before claims are submitted — the denial library's prevention checklists show the upstream fix for each code.
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