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Denial code decoder
41 CARC and RARC codes, written the way we'd explain them on a call: what the payer means, why it happened, and what to do about it.
41 of 41 codes
| Code | Plain English | Likely cause | Fix |
|---|---|---|---|
| CO-4CARC | Procedure code inconsistent with the modifier used, or a required modifier is missingThe payer accepted the procedure code but rejected the modifier combination attached to it. | Telehealth modifiers (95, GT) or place-of-service pairings applied inconsistently, or an add-on psychotherapy code billed without the modifier the payer expects. | Confirm the payer's current telehealth and add-on modifier policy, correct the modifier, and resubmit as a corrected claim rather than a new claim. |
| CO-11CARC | The diagnosis is inconsistent with the procedureThe payer does not accept the diagnosis code as medically supporting the service billed. | Z-code or unspecified diagnosis used as primary, or the diagnosis on the claim does not match the one documented in the note. | Pull the note, bill the most specific supported diagnosis as primary, and resubmit corrected. Fix the intake template if the pattern repeats. |
| CO-16CARC | Claim lacks information or has submission/billing errorsSomething required is missing or malformed. CO-16 almost always travels with a RARC that names the actual missing element. | Missing NPI or taxonomy, bad subscriber ID, missing rendering provider, or an incomplete supervising-provider loop for associate clinicians. | Read the accompanying RARC on the 835, not just the CARC. Correct the named field, and resubmit. Track which RARC pairs with CO-16 most often. |
| CO-18CARC | Exact duplicate claim or serviceThe payer believes this claim or line was already submitted. | A biller resubmitted instead of sending a corrected claim, or two clearinghouse submissions went out for the same date of service. | Check whether the original paid. If it did, no action. If it denied, submit a corrected claim with the proper frequency code instead of a fresh claim. |
| CO-22CARC | This care may be covered by another payer per coordination of benefitsThe payer thinks it is secondary, not primary. | Stale insurance on file, a new commercial plan, or Medicare/Medicaid COB not updated at intake. | Re-verify eligibility, confirm primary payer order with the patient, bill primary first, then submit secondary with the primary's 835 data. |
| CO-27CARC | Expenses incurred after coverage terminatedThe patient's plan was not active on the date of service. | No eligibility check at the time of service, or a plan that terminated mid-month. | Verify eligibility on every date of service. If coverage truly ended, rebill to the new payer or convert to patient responsibility per your financial policy. |
| CO-29CARC | The time limit for filing has expiredThe claim arrived after the payer's timely-filing deadline. | Claims that sat in a work queue, a credentialing gap that delayed submission, or denials that were never reworked before the clock ran out. | Appeal with proof of timely filing (clearinghouse acceptance reports). Then fix the upstream aging report so it cannot happen again. |
| CO-45CARC | Charge exceeds fee schedule or maximum allowable amountThe contractual write-down between your billed charge and the contracted allowed amount. | Normal on in-network claims. It is only a problem when the allowed amount is lower than your contracted rate. | Reconcile the allowed amount on every 835 line against your loaded fee schedule. Dispute any line allowed below contract. |
| CO-50CARC | Non-covered service, not deemed a medical necessityThe payer's medical-necessity criteria were not met by the information on the claim. | Session frequency beyond plan limits, diagnosis that does not support the level of service, or missing authorization details. | Appeal with the treatment plan and progress notes. If the plan explicitly excludes the service, move it to self-pay under a signed agreement. |
| CO-59CARC | Processed based on multiple or concurrent procedure rulesThe payer reduced payment because several procedures were performed on the same day. | Group plus individual therapy on one date, or an intake plus a psychotherapy session same day. | Verify the reduction matches published multiple-procedure policy; if the services are separately reportable, appeal with modifier support. |
| CO-96CARC | Non-covered charge(s)The service is excluded from the patient's benefit plan. | Behavioral health carve-out to a separate plan, or a service category the plan excludes outright. | Check whether behavioral health benefits are administered by a carve-out vendor and rebill there. Otherwise bill the patient per policy. |
| CO-97CARC | Benefit for this service is included in the payment for another service already adjudicatedThe payer bundled this line into another line it already paid. | Add-on codes billed alongside a primary service without correct modifiers, or NCCI edit pairs submitted together. | Run the code pair through NCCI edits. If the services were distinct, resubmit with modifier 25 or 59 and documentation supporting separateness. |
| CO-109CARC | Claim not covered by this payer or contractorYou sent the claim to the wrong payer or the wrong claims address. | Medicare Advantage plan billed as traditional Medicare, or a delegated behavioral health network missed at intake. | Re-verify the payer ID from the patient's card, then rebill to the correct entity. Watch the timely-filing clock, which is still running. |
| CO-119CARC | Benefit maximum for this time period or occurrence has been reachedThe patient exhausted a visit or dollar cap for the period. | Annual session limits under the plan, common with EAP and some commercial behavioral riders. | Track visit counts at scheduling. Request an extension or transition to self-pay before the cap is hit, not after. |
| CO-140CARC | Patient/insured health identification number and name do not matchDemographic mismatch between the claim and the payer's member record. | Typos at intake, a changed last name, or a dependent billed under the subscriber's ID. | Correct the member ID, legal name, and date of birth against the card, then resubmit. |
| CO-151CARC | Payer deems the information submitted does not support this many servicesFrequency or units exceed what the payer will accept for that period. | Twice-weekly therapy without authorization, or units billed on a code the payer treats as once-per-day. | Appeal with the treatment plan justifying frequency, or obtain authorization prospectively for higher-frequency care. |
| CO-167CARC | This diagnosis is not coveredThe plan excludes the diagnosis billed. | Adjustment or relational diagnoses on plans that only cover specified conditions. | Confirm the most clinically accurate covered diagnosis is sequenced first; do not upcode. If truly excluded, disclose self-pay in advance. |
| CO-170CARC | Payment denied when performed by this type of providerThe rendering provider's type or license is not eligible to bill this service under the plan. | Pre-licensed associates or residents billed under their own NPI instead of the supervising provider, a very common group-practice failure. | Bill under the credentialed supervising provider where contracts allow, and keep a credentialing matrix by payer and license type. |
| CO-181CARC | Procedure code was invalid on the date of serviceThe CPT or HCPCS code was not valid on that date. | Annual code-set change not loaded into the EHR, or a deleted telehealth code still in a favorites list. | Update the code set each January, purge retired favorites, and rebill with the valid code. |
| CO-197CARC | Precertification, authorization, or notification absentRequired prior authorization was not obtained or not on the claim. | Authorization expired mid-episode, unit count exhausted, or the auth number was never attached to the claim. | Request retro-authorization immediately because many payers allow a short window. Add an auth expiry alert to scheduling. |
| CO-204CARC | Service not covered under the patient's current benefit planThe plan does not include this service at all. | Couples or family therapy, coaching-style services, or testing on a plan without those benefits. | Verify benefits by CPT before the first session and collect a signed self-pay agreement where coverage does not exist. |
| CO-234CARC | This procedure is not paid separatelyThe code is only payable as part of another service. | Add-on or interactive-complexity codes billed standalone. | Bill the add-on on the same claim as its base code, in the correct line order. |
| CO-242CARC | Services not provided by a network or primary care providerThe payer processed the claim as out-of-network. | Clinician not yet loaded to the group contract, or a roster/effective-date gap after a new hire. | Confirm the effective date on the payer roster and appeal for retro in-network processing back to the credentialing effective date. |
| CO-252CARC | An attachment or other documentation is required to adjudicate this claimThe payer is waiting on records before it will pay. | Records requests routed to a fax number or portal nobody monitors. | Assign a single owner for documentation requests with a 5-business-day SLA, and log every submission with a confirmation. |
| PR-1CARC | Deductible amountThe dollars are the patient's unmet deductible, not a denial. | January and February sessions on high-deductible plans. | Verify deductible status before the session, collect at time of service, and reconcile PR-1 balances against patient payments monthly. |
| PR-2CARC | Coinsurance amountThe patient's percentage share of the allowed amount. | Normal adjudication on plans with coinsurance rather than a flat copay. | Quote coinsurance from the allowed amount, not the billed charge, and bill the patient promptly after the 835 posts. |
| PR-3CARC | Copayment amountThe patient's fixed per-visit amount. | Standard plan design; becomes a problem only when the copay was never collected. | Collect at check-in with a card on file, then reconcile collected copays against PR-3 lines on the remit. |
| PR-49CARC | Routine examination or screening procedure with a routine examThe payer treated the service as routine screening not covered under the plan. | Screening or wellness-style codes billed without a covered diagnosis or benefit. | Confirm whether preventive behavioral screening is a covered benefit; if not, disclose and bill the patient. |
| PR-96CARC | Non-covered charge(s), patient responsibilityNot covered, and the plan assigns the balance to the patient. | Service outside the benefit with a valid waiver or notice on file. | Bill the patient only if advance notice exists; otherwise the balance is not defensible and should be written off. |
| PR-119CARC | Benefit maximum reached, patient responsibilityThe plan cap is exhausted and remaining charges fall to the patient. | Session limits hit mid-year with no benefit tracking at scheduling. | Track remaining visits per patient and convert to a self-pay agreement before the cap, not after. |
| PR-204CARC | Service not covered under the current benefit plan, patient responsibilitySame exclusion as CO-204, but the balance is billable to the patient. | Non-covered service delivered without a signed self-pay acknowledgement. | Verify benefits by CPT before the first session and get the self-pay agreement signed at intake. |
| OA-18CARC | Exact duplicate claim or service (other adjustment)Duplicate flagged without assigning the balance to you or the patient. | Rebilling loops between an EHR and a clearinghouse. | Trace the original claim's status before resubmitting anything, and use corrected-claim frequency codes. |
| OA-23CARC | The impact of prior payer(s) adjudication including payments and/or adjustmentsThe secondary payer is showing what the primary already did. | Normal on secondary claims; a problem when the secondary balance is then never billed or posted. | Post primary and secondary remits in sequence and verify the remaining balance nets to zero or a valid patient balance. |
| OA-94CARC | Processed in excess of chargesThe payer paid more than the billed amount, or a posting mismatch exists. | Overpayment, duplicate payment, or a fee schedule loaded above the billed charge. | Identify overpayments proactively and refund or reserve for recoupment; unrecorded overpayments become surprise takebacks. |
| OA-121CARC | Outstanding balance on a previous claimThe payer is netting this payment against a prior balance owed. | Recoupment from an earlier overpayment on another claim or patient. | Match every recoupment on the 835 to the original claim so the offset reconciles to your bank deposit. |
| OA-192CARC | Non-standard adjustment code from a paper remittanceThe payer used a proprietary code that does not map cleanly to a standard reason. | Paper EOBs or non-compliant remittance formats, common with small or delegated plans. | Call the payer for the underlying reason and map it to a standard category so it is trackable in your denial reporting. |
| PI-204CARC | Not covered under the plan, payer-initiated reductionThe payer reduced payment on its own initiative and is not assigning it to the patient. | Plan-level policy edits applied after adjudication. | Request the written policy the reduction relies on, then appeal if the policy does not actually apply. |
| PI-97CARC | Bundled into another service, payer-initiatedThe payer bundled the line without making it a contractual write-off or patient balance. | Payer-specific bundling edits beyond standard NCCI pairs. | Compare against NCCI and your contract; appeal where the bundling is not contractually supported. |
| N130RARC | Consult plan benefit documents for information about restrictions for this serviceA remark code telling you the answer lives in the plan documents, not the remit. | Paired with CO-96 or CO-204 when a benefit restriction applies. | Pull the plan's behavioral health benefit grid once, store it, and stop re-verifying the same restriction claim by claim. |
| N290RARC | Missing, invalid, or incomplete rendering provider primary identifierThe remark that most often explains a CO-16 denial. | Rendering provider NPI missing from loop 2310B, common after onboarding a new clinician. | Add the rendering provider NPI and taxonomy to the claim template for every clinician before their first session bills. |
| MA04RARC | Secondary payment cannot be considered without the primary payer's informationThe secondary claim went out without primary adjudication data. | Secondary billing automated before the primary 835 posted. | Gate secondary submission on primary remit posting, and include the primary's adjustment detail on the claim. |
Reading these codes in context
The group prefix decides who absorbs the dollars. CO means the balance is your contractual write-off unless you appeal. PR means it is billable to the patient. OA is informational or an offset, and PI is a reduction the payer initiated on its own.
That distinction is where money hides. CO-45 is not a denial, so it never reaches a denial worklist. If the allowed amount is below your contracted rate, every one of those lines is an underpayment. Same story with PR-1 and PR-2 balances that post cleanly and then age into bad debt.