The denial code decoder

The plan had ended by the date of service. Verify the termination date on the eligibility response. If the patient had other active coverage, bill that payer; if not, this typically becomes patient responsibility when your intake paperwork supports it. Prevention: eligibility checks at scheduling, not after the visit.

Date of service precedes the plan's effective date. Confirm the effective date, check for retroactive coverage (common with Medicaid), and bill the correct payer or the patient accordingly.

The member ID, name, or date of birth does not match the payer's records. Re-verify against a current card image, fix the subscriber details, and resubmit. Watch for payer mergers that changed ID formats.

Coordination of benefits says someone else is primary. Ask the patient to update their COB with the payer (they usually must call), then resubmit to the correct primary. The claim will keep denying until the patient updates COB, so chase that call early.

Not really a denial: the secondary payer is showing what the primary already paid or adjusted. Post it and verify the remaining balance routed correctly to patient or write-off.

The plan simply does not cover this service. PR prefix means the patient owes it, provided your financial policy and any required notices (like an ABN for Medicare) were handled. Verify benefits before high-dollar services to avoid surprising patients.

The patient exhausted the visit or dollar cap (common in therapy). Track remaining benefits at check-in once a plan has caps; after the max, services are patient responsibility with proper notice.

Applied to the patient's deductible. Not an error: bill the patient. Eligibility responses show remaining deductible, so front desks can collect at the visit instead of chasing statements.

The patient's percentage share after the allowed amount. Post and bill the patient.

The flat visit fee. Ideally collected at check-in; if it lands on a remit, bill the patient.

Something required is missing or invalid, and the accompanying remark code (RARC, like N-series codes) says what. Read the remark, add the missing element, and resubmit as a corrected claim. No appeal needed, but the clock runs, so fix these the week they land.

The payer thinks it already has this claim. Check status of the original before resubmitting anything. If it was a legitimate repeat service on the same day, resubmit with the appropriate modifier (76, 77, or 59 depending on situation) and documentation.

Submitted after the payer's deadline. Winnable only with proof of timely original submission, like a clearinghouse acceptance report. Otherwise a write-off you cannot bill to the patient. Deadlines by payer live on the timely filing cheat sheet.

Wrong payer or wrong contractor: common with Medicare Advantage (bill the MA plan, not Medicare), managed Medicaid, and carve-outs like behavioral health. Identify the correct payer from the eligibility response and redirect the claim.

A catch-all that always travels with a remark code carrying the real reason. Decode the RARC on the same line and treat that as the actual denial.

The ICD-10 code was not valid on that date, usually after the October 1 code updates. Recode to the current-year code at full specificity and resubmit corrected.

Deleted or not-yet-effective CPT/HCPCS. Check the annual code changes (January 1 for CPT), swap to the valid code, resubmit corrected.

The modifier was deleted or does not apply. Confirm current-year modifier rules and resubmit with the correct one, or none.

The classic modifier denial. Determine which modifier the code combination needs (25 and 59 are the usual suspects), confirm documentation supports it, resubmit corrected. Scrubbing catches these before submission.

The diagnosis does not justify the procedure billed. Review the encounter documentation: either the diagnosis pointer is wrong (fixable) or the documented diagnosis genuinely does not support the service (provider query). Resubmit corrected or appeal with records.

Age-specific code mismatch, like an adult preventive code on a pediatric patient. Verify the DOB is right first, then swap to the age-appropriate code and resubmit.

The service needed prior auth and the claim shows none. If an auth existed, resubmit with the number. If not, appeal with a retro-authorization request where the payer allows it, and fix the front-end workflow that let an auth-required service through unflagged.

An auth exists but the number on the claim is wrong, expired, or covers different services or dates. Match the auth letter against the claim details exactly, correct, and resubmit.

The payer's coverage policy says the diagnosis does not justify the service. Check the payer's LCD/policy: if the documentation supports necessity, appeal with records; if a covered diagnosis was documented but not coded, correct the coding. For Medicare, an ABN converts these to patient responsibility when obtained beforehand.

The plan excludes this diagnosis. Confirm the coding reflects the documented condition; if it does, the balance follows your financial policy and plan rules. If a covered condition was under-coded, correct and resubmit.

Frequency or unit limits exceeded, like more visits than the policy allows in a period. Verify units billed, check the payer's frequency policy, and appeal with documentation when the extra services were justified.

A credentialing or enrollment gap on the date of service. Check the provider's effective dates with that payer. If credentialing was actually active, appeal with the approval letter; if not, this is usually unbillable and a lesson in not scheduling ahead of effective dates.

The payer does not pay this specialty or provider type for this service. Verify the taxonomy code on the claim matches the provider's enrollment; a wrong taxonomy is fixable, a true scope restriction is not.

Bundled: the payer says this service is part of another one billed the same day, or falls inside a global period. Check NCCI edits: if a distinct service was truly performed, appeal or resubmit with the appropriate modifier (59, or X-series for Medicare) and documentation. If it genuinely bundles, write it off.

Close cousin of CO-97: the code is never separately payable in this context. Verify with the payer's policy; usually a write-off unless billed in the wrong context.

An NCCI edit blocked the code pair or the modifier used to bypass it. Review the edit: if an override is legitimate, use the correct modifier with documentation; otherwise remove the conflicting line.

Usually not an error at all: it is the contractual adjustment between your charge and the allowed amount. Post it. It only becomes a problem when the allowed amount is below your contracted rate, which is an underpayment worth disputing, so spot-check CO-45 lines against your fee schedule.

Second and subsequent procedures paid at reduced rates per policy (often 50 percent). Expected behavior, not a denial. Verify the reduction matches the contract and post.

The federal 2 percent Medicare payment reduction. Not appealable, not patient-billable. Post as an adjustment.

The payer wants records before it will adjudicate. Send exactly what the remark code asks for, referencing the claim number, within the response window. Track it like an appeal deadline.

This code only pays alongside a primary service the payer has no record of, common with add-on codes. Confirm the primary procedure was billed and paid; resubmit together if the primary went missing.