[ { "code": "CO-16", "group": "CO", "summary": "The claim is missing information the payer needs, or something on it is inconsistent. It is the most common denial there is, and on its own it tells you almost nothing — the useful detail is always in the remark codes sitting next to it.", "causes": [ "A required field is blank or malformed: subscriber ID, date of birth, referring provider NPI, place of service.", "The diagnosis code is invalid, truncated, or was deleted in a previous code year.", "A code that requires a seventh character was submitted without one, so it is not a valid code at all.", "A non-billable header code (a category rather than a specific code) was submitted as if it were billable.", "Required documentation or an attachment the payer expected was not received." ], "fix": [ "Read the RARC codes on the same remittance line. CO-16 is a container; the remark code tells you what is actually missing.", "Check the diagnosis codes first — invalid and incomplete codes are the single most common cause, and they are also the easiest to verify.", "Correct the specific field and resubmit as a corrected claim. CO-16 is almost always correctable rather than appealable." ], "prevent": "Most of the coding causes are detectable before submission. An incomplete code, a deleted code, or a header code billed as specific are all visible the moment the diagnosis set is checked.", "scrubbable": true, "appealable": false, "related": [ "co-11", "co-4", "ma130", "n382" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-16" }, { "code": "CO-97", "group": "CO", "summary": "The service is considered already paid for as part of another service on the same claim. This is bundling: the payer says you billed separately for something that was included in the price of something else.", "causes": [ "The two procedures are bundled under a payer edit — the second is treated as a component of the first.", "The service falls inside another procedure's global surgical period.", "A modifier that would have made the second service separately payable was missing, or was not supported by the documentation.", "The same service was billed twice, once bundled into a comprehensive code and once on its own." ], "fix": [ "Check whether an unbundling modifier legitimately applies. If it does, and the documentation genuinely supports a distinct service, append it and resubmit.", "Do not simply add a modifier to force payment. An unsupported modifier is what a payer audit looks for, and it converts a denial into a repayment demand.", "If the service really is bundled, write it off. Appealing a correct bundling edit wastes more than it recovers." ], "prevent": "Bundling is decided by procedure-to-procedure edits, which are published quarterly. Checking the pair before submission is a two-second operation; discovering it on the remit costs a rework cycle.", "scrubbable": false, "appealable": false, "related": [ "co-59", "co-18" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-97" }, { "code": "CO-45", "group": "CO", "summary": "Your charge was above the payer's allowed amount, and the difference is a contractual write-off. This is not really a denial — it is the contract working exactly as written, and there is usually nothing to appeal.", "causes": [ "Your fee schedule is set above the payer's allowed amount. That is normal and expected.", "The payer priced the service using a different fee schedule than you assumed.", "A pricing modifier changed the allowed amount." ], "fix": [ "Nothing, in most cases. Adjust the difference off as contractual. Billing the patient for it would breach your participation agreement.", "Do check the allowed amount is right. If the payer priced the service below the fee schedule you contracted at, that is worth disputing — but the dispute is about the rate, not the denial." ], "prevent": "You cannot prevent CO-45 and should not try to. What you can do is know the allowed amount before you bill, so the write-off is expected rather than a surprise in the month-end numbers.", "scrubbable": false, "appealable": false, "related": [ "pr-1", "pr-2", "pr-45", "co-253" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-45" }, { "code": "CO-50", "group": "CO", "summary": "The payer does not consider the service medically necessary for the diagnosis you submitted. In Medicare, this almost always means the diagnosis is not on the covered list in the applicable coverage policy for your jurisdiction.", "causes": [ "The diagnosis code does not appear in the covered list of the Local Coverage Determination or coverage article that governs the service.", "A more specific diagnosis exists in the chart that would have supported necessity, and an unspecified code was submitted instead.", "The diagnosis is genuinely not covered for this service, and the patient should have signed an ABN.", "The coverage policy changed and the claim was coded against the old one." ], "fix": [ "Read the actual coverage policy for your Medicare contractor. Coverage is jurisdictional — the same code can be covered in Texas and not in Ohio.", "If the documentation supports a diagnosis that IS on the covered list, recode and resubmit. If it does not, do not code one that is not supported.", "If an ABN was signed, bill the patient with the appropriate modifier. If it was not, the write-off is yours." ], "prevent": "Medical necessity is knowable before submission. The coverage policy for your contractor is published, it is public, and it names the diagnoses it will accept.", "scrubbable": true, "appealable": true, "related": [ "co-16", "co-151", "co-55" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-50" }, { "code": "CO-11", "group": "CO", "summary": "The diagnosis does not match the procedure. The payer is saying the reason you gave for the service does not justify the service you performed.", "causes": [ "The diagnosis submitted genuinely does not support the procedure.", "The right diagnosis is in the chart but a different one was linked to the line item.", "The diagnosis pointer on the claim line points at the wrong diagnosis.", "An unspecified code was used where a specific one would have supported the service." ], "fix": [ "Check the diagnosis pointers first. A correct diagnosis linked to the wrong line is one of the most common versions of this, and it is a clerical fix.", "Re-read the documentation for a diagnosis that supports the service. If one exists and was simply not coded, recode and resubmit." ], "prevent": "Most of these are a mismatch the coder could have seen. The rest are coverage-policy problems, which are also knowable in advance.", "scrubbable": true, "appealable": false, "related": [ "co-16", "co-50" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-11" }, { "code": "CO-4", "group": "CO", "summary": "The procedure code is inconsistent with the modifier used, or a required modifier is missing. The payer is telling you the modifier and the code do not go together.", "causes": [ "A required modifier was not appended.", "A modifier was appended that is not valid with that procedure code.", "The modifier contradicts the code — for example a laterality modifier on a bilateral code.", "Modifiers were sequenced incorrectly." ], "fix": [ "Check which modifiers are valid for the code, and whether the documentation supports the one you used.", "Never add a modifier purely to get paid. An unsupported modifier is exactly what an audit is looking for." ], "prevent": "Modifier rules are published. The mismatch is visible before the claim goes out, not only after it comes back.", "scrubbable": false, "appealable": false, "related": [ "co-97", "co-16" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-4" }, { "code": "CO-18", "group": "CO", "summary": "Duplicate claim or service. The payer believes it has already received this exact claim, or already paid for this exact service.", "causes": [ "The claim really was submitted twice — often because the first submission was thought to have failed.", "The same service was billed on two separate claims for the same date of service.", "A legitimately repeated service on the same day was billed without the modifier that says it was distinct and repeated.", "A corrected claim was submitted as a new claim rather than as a replacement." ], "fix": [ "Check whether the original was actually paid before doing anything else. Resubmitting a paid claim compounds the problem.", "If the service genuinely was performed more than once that day, the repeat needs the appropriate modifier and the documentation to support it.", "If it is a correction, submit it as a corrected claim, not a fresh one." ], "prevent": "This is a workflow problem more than a coding one — but repeated same-day services are a coding decision, and they need the modifier at the time of coding, not after the denial.", "scrubbable": false, "appealable": false, "related": [ "co-97", "oa-18" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-18" }, { "code": "CO-29", "group": "CO", "summary": "The claim was filed after the payer's deadline. Timely filing limits are contractual, they are strict, and this denial is usually final.", "causes": [ "The claim genuinely was submitted late.", "The claim was submitted on time but to the wrong payer, and the clock kept running.", "The claim was rejected at the clearinghouse and never actually reached the payer — a rejection is not a submission.", "The original was submitted on time but a corrected claim was filed after the limit." ], "fix": [ "Find proof of timely submission. A clearinghouse acknowledgement showing the payer accepted the claim within the window is the thing that overturns this.", "If it was rejected rather than denied, the rejection report is your evidence that you tried — but it may also be evidence you never actually filed.", "Appeal with the documentation. Without proof, this one usually stands." ], "prevent": "Watch the rejections, not just the denials. A claim sitting in a clearinghouse rejection queue is a claim that was never filed, and the timely filing clock does not care.", "scrubbable": false, "appealable": true, "related": [ "ma130" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-29" }, { "code": "CO-109", "group": "CO", "summary": "This claim is not payable by this payer or contractor. You sent it to the wrong place.", "causes": [ "The patient is enrolled in a Medicare Advantage plan, and the claim went to traditional Medicare.", "The service is covered by a different contractor or a different jurisdiction.", "The patient has other primary insurance and Medicare is secondary." ], "fix": [ "Verify eligibility and find out who the correct payer actually is, then submit there.", "Watch the timely filing clock. It is running for the correct payer, and it has been running the whole time you were waiting on this denial." ], "prevent": "This is an eligibility problem, and eligibility is checkable before the visit rather than after the denial.", "scrubbable": false, "appealable": false, "related": [ "co-29" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-109" }, { "code": "CO-151", "group": "CO", "summary": "The payer says the information submitted does not support this many services. You billed more units than they will accept for that code.", "causes": [ "The units billed exceed the payer's published limit for that code.", "Units were miscalculated — billing minutes as units, or the reverse.", "The service genuinely was performed more times than the limit allows, and the documentation to justify it was not submitted." ], "fix": [ "Check the units against the published limit for that code before appealing. If you exceeded it, the appeal needs documentation, not indignation.", "If the units were simply miscalculated, correct and resubmit." ], "prevent": "Unit limits are published quarterly and are checkable before submission. Exceeding one is not something you should learn from a remittance.", "scrubbable": false, "appealable": true, "related": [ "co-97", "pr-119" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-151" }, { "code": "PR-1", "group": "PR", "summary": "The amount is applied to the patient's deductible. Not a denial at all — the payer is telling you the patient has not met their deductible yet and this amount is theirs to pay.", "causes": [ "The patient's annual deductible has not been satisfied.", "It is early in the plan year and most patients have not met it." ], "fix": [ "Bill the patient. This is patient responsibility and it is legitimately collectible.", "Check it against the patient's benefits if the amount looks wrong." ], "prevent": "Nothing to prevent. But knowing the deductible status at check-in means you can collect it then, rather than chasing it for ninety days afterwards.", "scrubbable": false, "appealable": false, "related": [ "pr-2", "pr-3", "co-45" ], "url": "https://medicalcodingsoftware.org/denial-codes/pr-1" }, { "code": "PR-2", "group": "PR", "summary": "Coinsurance. The patient's share of the allowed amount, typically 20% under Medicare. Also not a denial.", "causes": [ "The plan's coinsurance percentage applied normally." ], "fix": [ "Bill the patient, or their secondary insurance if they have one." ], "prevent": "Nothing to prevent. This is the plan design working as intended.", "scrubbable": false, "appealable": false, "related": [ "pr-1", "pr-3" ], "url": "https://medicalcodingsoftware.org/denial-codes/pr-2" }, { "code": "PR-3", "group": "PR", "summary": "Copay. A fixed amount the patient owes for the visit. Not a denial.", "causes": [ "The plan has a fixed copay for this service type." ], "fix": [ "Collect from the patient. Ideally you already did, at check-in." ], "prevent": "Nothing to prevent — but a copay collected at the desk costs nothing to collect.", "scrubbable": false, "appealable": false, "related": [ "pr-1", "pr-2" ], "url": "https://medicalcodingsoftware.org/denial-codes/pr-3" }, { "code": "CO-96", "group": "CO", "summary": "Non-covered charge. The service is not a benefit under the patient's plan at all — this is different from 'not medically necessary', which is CO-50.", "causes": [ "The service is genuinely excluded from the plan's benefits.", "The service is statutorily excluded (Medicare does not cover it for anyone).", "A coding error made a covered service look like a non-covered one." ], "fix": [ "Check first whether the service is truly non-covered or whether the coding made it look that way.", "If an ABN was signed, bill the patient with the appropriate modifier. If not, you absorb it.", "Statutory exclusions cannot be appealed. Benefit exclusions rarely can." ], "prevent": "Know before the service whether it is covered, and get the ABN signed if it is not. Afterwards is too late to ask.", "scrubbable": false, "appealable": false, "related": [ "co-50", "pr-96", "pr-204" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-96" }, { "code": "CO-22", "group": "CO", "summary": "The payer believes another insurer should pay first. This is a coordination-of-benefits denial: they are not saying the service isn't covered — they are saying they are not the one who covers it first, and they want the other payer's answer before giving theirs.", "causes": [ "The patient has other coverage that is primary: a working spouse's plan, an employer plan alongside Medicare, or Medicare Advantage when the claim went to traditional Medicare.", "The visit is accident-related, so auto, liability, or workers' compensation coverage comes first.", "The payer's coordination-of-benefits records are stale — the other coverage ended years ago, but nobody told them.", "The patient never answered the payer's COB questionnaire, so the payer defaulted to 'someone else is primary'." ], "fix": [ "Verify eligibility and ask specifically about other coverage. The order of payers is determined by rules (employment status, birthday rule for dependents, accident type), not by whichever card the patient handed you.", "If another payer really is primary, bill them first, then resubmit here with the primary's remittance attached.", "If there is no other coverage, the patient usually has to say so themselves — have them call the payer and update their COB record. Payers routinely refuse to take the provider's word for it." ], "prevent": "Ask about other coverage and accident involvement at check-in, every time. The COB question takes thirty seconds at the desk and thirty days on a remit. You may also see this with a PR prefix (PR-22) when the payer assigns the sorting-out to the patient.", "scrubbable": false, "appealable": false, "related": [ "co-24", "oa-23", "co-109" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-22" }, { "code": "OA-23", "group": "OA", "summary": "The amount reflects what a prior payer already did with this claim. You see this on secondary claims: it is the primary insurer's payment and adjustments being carried over, not a new decision by the secondary. It is arithmetic, not a denial.", "causes": [ "The claim was processed as secondary, and the primary's payment plus its adjustments account for this amount.", "A Medicare crossover claim reached the supplemental payer with Medicare's adjudication attached." ], "fix": [ "Usually nothing. Check the math: the secondary's allowed amount, minus what the primary paid and adjusted, should equal what the secondary handled. OA-23 is the carried-over piece.", "Do not bill the patient for the OA-23 amount. It was already resolved — paid or written off — at the primary. The patient's actual share is whatever the remit assigns to PR codes.", "If the primary's payment shown here doesn't match the primary's own remit, the secondary processed from bad numbers — send them the primary EOB and ask for reprocessing." ], "prevent": "Nothing to prevent. Expect it on every secondary claim, and make sure your posting rules don't treat it as a balance to chase. The CO-23 variant means the same carried-over adjudication, grouped as contractual.", "scrubbable": false, "appealable": false, "related": [ "co-22", "co-45" ], "url": "https://medicalcodingsoftware.org/denial-codes/oa-23" }, { "code": "PR-96", "group": "PR", "summary": "Non-covered charge, and the patient owes it. Same reason as CO-96 — the service is not a benefit — but the PR prefix moves the money: instead of a write-off, the payer is saying this amount is legitimately billable to the patient.", "causes": [ "The service is excluded under the patient's plan, and the payer holds the patient responsible for exclusions.", "For Medicare: a valid ABN was on file, so the statutorily or medically non-covered service shifts to the patient as intended.", "A coding error made a covered service look like an excluded one — worth ruling out before anyone gets a bill." ], "fix": [ "Confirm the exclusion is real before billing the patient. Pull the benefit language or call — a wrong code can manufacture a 'non-covered' out of a covered service.", "Check your notice obligations. Medicare wants a valid ABN signed before the service; many commercial contracts require advance notice before you can collect for non-covered care. If the notice wasn't given, the PR prefix does not automatically make the balance collectible.", "If the exclusion was misapplied, appeal with the benefit language and the corrected coding. If it is genuine and your notices are in order, bill the patient — this one is theirs." ], "prevent": "Verify benefits for the service category before rendering it, and get the ABN or waiver signed when coverage is doubtful. The moment to establish who pays is before the service, not on the remit.", "scrubbable": false, "appealable": true, "related": [ "co-96", "co-50", "pr-204" ], "url": "https://medicalcodingsoftware.org/denial-codes/pr-96" }, { "code": "PR-204", "group": "PR", "summary": "The service is not covered under the patient's current benefit plan, and the balance is the patient's. Close cousin of PR-96, with one trap worth knowing: 'not covered under THIS plan' sometimes means covered under a different one the patient also has.", "causes": [ "The service category simply isn't in the plan: hearing aids, routine vision, cosmetic procedures, adult dental under a medical plan.", "The benefit is carved out to another entity — behavioral health, dental, vision and pharmacy are routinely administered by a separate company, and the medical payer denies its half truthfully.", "The plan changed at renewal, and last year's covered service is this year's exclusion." ], "fix": [ "Check for a carve-out before accepting the denial at face value. If behavioral health is administered separately, the claim isn't non-covered — it went to the wrong company. Find the right one and file there, watching their timely filing clock.", "Verify the benefit with the current plan year, not your notes from last year.", "If it is genuinely excluded and your notice obligations are met, bill the patient. If the payer misread its own plan, appeal with the benefit language." ], "prevent": "Benefit verification that names the specific service category, and a note of which benefits are carved out to whom. The CO-204 variant means the same thing with the write-off assigned to you instead — usually a network-contract consequence.", "scrubbable": false, "appealable": true, "related": [ "pr-96", "co-96" ], "url": "https://medicalcodingsoftware.org/denial-codes/pr-204" }, { "code": "OA-18", "group": "OA", "summary": "Exact duplicate. The payer's system matched this claim against one it already has — same patient, provider, service, and date — and rejected the copy automatically. The OA prefix is how it usually arrives when the payer treats it as neither your write-off nor the patient's bill: just a duplicate to discard.", "causes": [ "The claim was resubmitted while the original was still working its way through adjudication.", "The original was assumed lost — often because the acknowledgement was never checked — and a second copy was fired off.", "The claim went out both electronically and on paper, or a system interface resent a batch.", "A corrected claim was submitted as a brand-new claim instead of a replacement, so it collided with the original." ], "fix": [ "Check the status of the original first. If it is pending, wait; if it paid, post it and close this one; if it denied, work that denial rather than this echo of it.", "If the 'duplicate' was actually a distinct second service on the same day, resubmit with the modifier that says so, and documentation that supports it.", "If it is a correction, resubmit as a corrected claim with the original claim number referenced — not as a fresh submission." ], "prevent": "Resubmit on evidence, not anxiety. A claim-status check costs seconds; a duplicate cycle costs weeks and makes your submission history look sloppier with every round.", "scrubbable": false, "appealable": false, "related": [ "co-18", "co-129" ], "url": "https://medicalcodingsoftware.org/denial-codes/oa-18" }, { "code": "CO-197", "group": "CO", "summary": "No prior authorization. The payer required precertification for this service and cannot find one — either it was never obtained, or it was obtained and the claim doesn't show it. Among the most expensive denials there is, and one of the most appealable.", "causes": [ "Authorization genuinely was never requested — the service wasn't on anyone's list of things that need it, or the requirement was added recently.", "An authorization exists but the number never made it onto the claim.", "The authorization doesn't match the claim: different procedure, different date range, different rendering provider or site, or the approved units ran out.", "The authorization expired before the service happened, often because scheduling slipped." ], "fix": [ "If an authorization exists, this is the easy version: resubmit or appeal with the authorization number and the approval letter. Mismatches (date, provider, units) go to the payer with an explanation of the discrepancy.", "If it was never obtained, ask about retroactive authorization immediately — many payers allow it in a narrow window, and 'immediately' is the operative word for urgent or add-on services.", "If retro-auth is refused, appeal on the merits: why the service was needed, why obtaining authorization first wasn't possible (urgent finding, service added intraoperatively), and the clinical documentation. Payers overturn more of these than they advertise." ], "prevent": "Make authorization a scheduling gate, not a billing discovery. Track four things per auth: the number, the exact codes approved, the date window, and the units — a mismatch on any one of them lands you back on this page.", "scrubbable": false, "appealable": true, "related": [ "co-252", "co-288", "co-50" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-197" }, { "code": "PR-31", "group": "PR", "summary": "The payer cannot match the patient to a member. The ID, name, or date of birth on the claim doesn't line up with anyone on their rolls — so before arguing about coverage, there is no patient to argue about.", "causes": [ "A digit off in the member ID, a misspelled name, a transposed date of birth. Clerical causes dominate this denial.", "The patient handed over an old card after switching plans, and the claim went to last year's payer.", "A newborn being billed under their own name before the plan has actually added them to the policy.", "The payer migrated or merged member IDs and the one on file with you no longer exists." ], "fix": [ "Re-verify with the physical card and a fresh eligibility check. Correct the identifier and resubmit — this is a correction, not an appeal.", "If the plan changed, find the right payer and submit there, minding their timely filing limit, which has been running since the date of service.", "For newborns, get the enrollment completed (the parents may need to act) and resubmit once the child exists in the payer's system." ], "prevent": "Scan the card and run eligibility at every visit, not just the first one. Coverage changes in January and at every job change, and the front desk is the only place this denial can actually be prevented.", "scrubbable": false, "appealable": false, "related": [ "co-16", "n382", "pr-27" ], "url": "https://medicalcodingsoftware.org/denial-codes/pr-31" }, { "code": "CO-252", "group": "CO", "summary": "The payer wants documentation before it will decide. This is not a final denial — it is a request: send the records, and adjudication continues. Treat it like a deadline, because that is what it is; ignored, it hardens into a denial that is much more work to reopen.", "causes": [ "The claim hit a threshold that triggers manual review: high dollar amount, an unlisted or rarely-billed code, or a modifier that promises documentation (22, 25, 59 and friends).", "The payer has the provider or the code under a prepayment review program.", "An attachment the claim referenced never arrived or never got linked." ], "fix": [ "Read the remark codes on the line — they name what is wanted. Send exactly that, not the whole chart.", "Use the payer's stated channel and reference the claim number and any request ID, so the response actually attaches to the claim instead of landing in a general queue.", "Calendar the deadline the moment this arrives. A complete response sent late is the same as no response." ], "prevent": "Learn which of your codes and modifiers reliably trigger documentation requests, and send the records with the claim. One mailing beats a request-response cycle every time.", "scrubbable": false, "appealable": false, "related": [ "co-226", "pr-227", "co-16" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-252" }, { "code": "N130", "group": "RARC", "summary": "A remark code pointing you at the plan's benefit documents: the adjustment next to it is driven by something in the plan itself — a limit, a restriction, a condition of coverage. The reason code on the line says what happened; N130 says where the rule lives.", "causes": [ "A frequency or quantity limit in the plan: one screening per year, so many visits per condition, replacement schedules for equipment.", "A plan-level restriction on the setting, the provider type, or the circumstances under which the service is covered.", "A benefit that exists but with conditions the claim didn't meet." ], "fix": [ "Start with the reason code next to it — N130 qualifies a denial, it isn't one by itself.", "Get the actual benefit language: the provider portal, a benefits call with the reference number written down, or the patient's own plan documents.", "If the restriction was applied wrongly — the count is off, the condition was met — appeal citing the plan's own language. Their document is the strongest exhibit you can attach." ], "prevent": "For services with known frequency limits, verify the remaining benefit before scheduling. The plan document always wins; the only question is whether you read it before the service or after the denial.", "scrubbable": false, "appealable": false, "related": [ "pr-119", "pr-204", "pr-96" ], "url": "https://medicalcodingsoftware.org/denial-codes/n130" }, { "code": "CO-24", "group": "CO", "summary": "The charge is covered under a capitation arrangement or managed care plan — meaning fee-for-service payment doesn't apply. Most often this is a Medicare claim for a patient who is actually enrolled in a Medicare Advantage plan.", "causes": [ "The patient is in a Medicare Advantage plan and the claim went to traditional Medicare, which correctly answers that it no longer pays for this patient.", "The service falls under a capitation agreement — a monthly per-member payment to a PCP, IPA, or medical group already covers it, so a separate claim has nothing to attach to.", "The patient switched into or out of a managed care plan and the enrollment records lag reality." ], "fix": [ "Verify enrollment for the date of service and find out who actually holds the risk: the MA plan, the medical group, the IPA.", "Rebill the correct entity. An MA plan claim goes to the plan, not to Medicare; a capitated service may need to go to the group that holds the capitation.", "If you are the capitated provider, there is nothing to collect — the monthly payment was the payment. Writing this off correctly matters for your books." ], "prevent": "Eligibility checks that surface plan enrollment, not just 'active coverage'. Medicare Advantage enrollment is exactly the kind of fact a yes/no eligibility ping hides and a proper check reveals.", "scrubbable": false, "appealable": false, "related": [ "co-22", "co-109", "co-256" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-24" }, { "code": "CO-234", "group": "CO", "summary": "This procedure is not paid separately — and the remark code next to it says why. The payer isn't disputing that you did it; they are saying its payment lives inside something else on the claim, or that on its own it isn't a payable line at all.", "causes": [ "The service is considered a component of another procedure billed the same day.", "An add-on style code was billed without the primary service it attaches to.", "Payer payment policy folds this service into a global or composite payment." ], "fix": [ "Read the remark code first — CO-234 never travels alone, and the RARC carries the actual reason.", "Check whether the primary procedure was billed and paid. An add-on denied because its primary is missing is fixed by sorting out the primary, not by appealing the add-on.", "If the service genuinely stands alone — separate session, separate site, separate indication — appeal with documentation that shows the separation. If it doesn't, the write-off is correct and it is contractual, not billable to the patient." ], "prevent": "Know your add-on pairings and the services your major procedures absorb. That knowledge is published payment policy, and checking it at coding time is cheaper than discovering it at posting time.", "scrubbable": false, "appealable": false, "related": [ "co-97", "co-59", "n19" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-234" }, { "code": "CO-226", "group": "CO", "summary": "The payer asked the billing provider for information and considers the answer missing, incomplete, or late. Somewhere there is a development letter with your name on it — the entire game is finding it and answering it properly.", "causes": [ "A records request went to an address or fax you stopped watching, and the response window expired quietly.", "Records were sent but incomplete — the request asked for three things and got two.", "The response was sent without the claim or request identifiers, so it never got matched to the claim it was meant to save.", "The response was simply late." ], "fix": [ "Find the original request. Call the payer if you have to — you need to know exactly what was asked and when the clock started.", "Send a complete response through the payer's stated channel, referencing the claim number and the request ID on every page.", "If you can show you never received the request — wrong address on their file, no delivery — appeal on that basis and get your correspondence address corrected while you are at it." ], "prevent": "Payer correspondence needs a work queue with deadlines, the same as denials do. A development letter aging in a mail tray is a denial with a countdown attached.", "scrubbable": false, "appealable": true, "related": [ "co-252", "pr-227" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-226" }, { "code": "PR-227", "group": "PR", "summary": "The payer asked the patient for information and never got it, so the claim is denied to the patient. Common after anything accident-shaped: the payer sends the member a questionnaire, the member ignores it, and your claim pays for their silence.", "causes": [ "A coordination-of-benefits or 'do you have other insurance' questionnaire went unanswered.", "An accident-details questionnaire (was this an auto accident? work-related?) sat on the patient's kitchen counter.", "A student-status or dependent-eligibility verification was never returned." ], "fix": [ "Contact the patient, tell them exactly what the payer sent them, and have them call the number on their card to answer it. Most patients have no idea their unanswered mail is why they got a bill.", "Once the member responds, ask the payer to reprocess — this usually reopens without a formal appeal.", "Document your outreach. If the patient never responds, the PR grouping means the balance is genuinely theirs, and your records show you tried to help them avoid it." ], "prevent": "Warn patients at intake — especially after injuries — that their insurer may mail them a questionnaire, and that ignoring it turns a covered visit into their bill. One sentence at the desk prevents most of these.", "scrubbable": false, "appealable": false, "related": [ "co-226", "co-22", "pr-31" ], "url": "https://medicalcodingsoftware.org/denial-codes/pr-227" }, { "code": "CO-236", "group": "CO", "summary": "This procedure isn't compatible with another procedure billed on the same day, under the coding rules the payer applies. It is the procedure-pair denial: not 'you can't do both', but 'you can't be paid separately for both the way this was coded'.", "causes": [ "The pair falls under a procedure-to-procedure edit that treats one service as included in the other.", "Two codes describe overlapping work, and the guidelines say report the more comprehensive one alone.", "A same-day pairing that is only payable with a modifier attesting the services were distinct — different session, site, or indication — billed without one." ], "fix": [ "Look up the pair before reacting. If the edit allows a modifier and the documentation genuinely supports distinct services, correct and resubmit.", "If the documentation does not support separating them, the adjustment stands and it is yours — CO means no patient billing.", "Never append a bypass modifier just to get paid. That specific move is what payer audits are built to find, and it converts a denial into a refund demand with interest." ], "prevent": "Same-day code pairs are checkable before submission against published edits. Our scrubber cannot do this one for you yet — the edits are keyed to CPT codes, which aren't included yet — but your clearinghouse or encoder may.", "scrubbable": false, "appealable": false, "related": [ "co-97", "co-4", "co-234" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-236" }, { "code": "CO-253", "group": "CO", "summary": "Sequestration. A federal budget-law reduction — 2% off Medicare's payment — applied after everything else is calculated. It is not a denial, not appealable, and not the patient's problem. It is an Act of Congress, literally.", "causes": [ "Federal sequestration applied to Medicare fee-for-service payments.", "A Medicare Advantage plan passing the same reduction through, where the contract allows it." ], "fix": [ "Post it as the contractual adjustment it is. There is nothing to correct, resubmit, or appeal.", "Make sure your posting rules never shift this amount to the patient. It comes off the payer's 80%, not the beneficiary's share.", "If the amount isn't roughly 2% of the Medicare payment, something else is on the line — read the other codes." ], "prevent": "Nothing to prevent — build it into expected reimbursement so month-end doesn't keep rediscovering it. When your Medicare payments all arrive 2% light, this is why.", "scrubbable": false, "appealable": false, "related": [ "co-45" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-253" }, { "code": "PR-119", "group": "PR", "summary": "The benefit maximum has been reached — the plan's allowance for this service, this period, is used up, and further charges belong to the patient. The useful question is always: used up according to whom, and is their count right?", "causes": [ "An annual visit or dollar cap exhausted: therapy visits, chiropractic, acupuncture are the classics.", "A frequency limit on equipment or supplies — the plan replaces so many per period, and this one exceeded it.", "Care split across multiple providers, each unaware how much of the benefit the others consumed.", "A lifetime maximum, for the benefits that still have one." ], "fix": [ "Get the payer's count and compare it to yours. Counts go wrong — retro-adjusted claims, another provider's visits, a plan-year boundary — and a wrong count is very appealable with a visit ledger attached.", "If the maximum is genuinely reached, the balance is the patient's; tell them where they stand and check any secondary coverage.", "For ongoing therapy, discuss the remaining course with the patient now, not visit by visit as each claim bounces." ], "prevent": "Track remaining benefits for cap-limited services at scheduling. 'You have four visits left' is a conversation; discovering it on a remit is a collection problem. The CO-119 variant assigns the excess to you instead — usually your network contract's no-balance-billing clause at work.", "scrubbable": false, "appealable": true, "related": [ "n130", "pr-204" ], "url": "https://medicalcodingsoftware.org/denial-codes/pr-119" }, { "code": "PR-242", "group": "PR", "summary": "The services weren't provided by a network or primary-care provider, so the plan is paying less or nothing and assigning the difference to the patient. Before anyone bills the patient, one question matters most: are you actually out of network, or do the payer's records just say so?", "causes": [ "The rendering provider genuinely isn't in this plan's network — being in-network with the payer's other products doesn't count.", "The patient's HMO requires care through their PCP, and this wasn't.", "The provider's roster entry is wrong or lapsed — a credentialing or re-enrollment gap making an in-network provider look OON.", "The claim's NPI or tax ID doesn't match the contracted entity, so the match fails on paperwork." ], "fix": [ "Verify your own participation status for this specific plan first. If you are contracted, dispute with your contract and roster evidence — this happens more than payers like to admit, especially after mergers and re-credentialing cycles.", "Check whether federal or state surprise-billing protections apply — emergency care and out-of-network providers at in-network facilities generally can't be balance-billed beyond in-network cost sharing.", "If you are genuinely out-of-network and no protection applies, the patient's OON benefits govern; bill accordingly and tell them why." ], "prevent": "Verify network participation per plan — not per payer — at scheduling, and keep your credentialing and payer rosters current. A lapsed re-attestation shows up in the world as a wave of these. The CO-242 variant means your contract eats the difference instead.", "scrubbable": false, "appealable": true, "related": [ "co-288", "pr-204", "co-8" ], "url": "https://medicalcodingsoftware.org/denial-codes/pr-242" }, { "code": "CO-59", "group": "CO", "summary": "The payment was processed under multiple-procedure or concurrent-procedure rules. Usually a reduction rather than a denial: when several procedures happen in one session, the first pays in full and the rest pay at a discount, on the theory that the overhead only happened once.", "causes": [ "Multiple procedures in one session — the highest-valued pays at 100% and subsequent ones at reduced rates.", "Multiple imaging or therapy services subject to the payer's multiple-procedure payment reductions.", "Concurrent services (anesthesia, monitoring) paid under their own concurrency rules." ], "fix": [ "Check the ranking. The reduction is supposed to hit the lesser-valued procedures; if the payer discounted the wrong line, request reprocessing with the correct ranking.", "Recalculate what the claim should pay under the reduction rules and compare. Correct math gets posted, not appealed.", "Remember CO means contractual: the reduced amount is a write-off, not a patient bill." ], "prevent": "Nothing to prevent — but know your multiple-procedure exposure when estimating, so a surgical claim paying 'short' is expected arithmetic rather than a monthly surprise.", "scrubbable": false, "appealable": false, "related": [ "co-45", "co-97", "co-234" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-59" }, { "code": "CO-131", "group": "CO", "summary": "A claim-specific negotiated discount was applied — a rate agreed for this claim rather than by your standing contract. Fine when you actually negotiated one. The reason to read this page: sometimes you didn't, and the discount is riding on an agreement you never signed.", "causes": [ "A single-case agreement you negotiated for an out-of-network patient, applied as agreed.", "A third-party repricer or rental-network discount applied to an out-of-network claim — sometimes with authority, sometimes on the strength of a network you never joined.", "A prompt-pay or settlement arrangement showing up as a line-level discount." ], "fix": [ "Match the discount to a document. If there is a single-case agreement, check the remit against its terms and hold the payer to them.", "If no agreement authorizes it, ask the payer in writing for the contractual basis of the discount. A discount with no contract behind it is disputable, and worth disputing.", "Post correctly either way — an agreed discount is a write-off; an unauthorized one is short payment." ], "prevent": "Keep single-case agreements where billing can see them, and reconcile OON payments against what was actually agreed rather than what arrived. Unauthorized discounts count on nobody checking.", "scrubbable": false, "appealable": true, "related": [ "co-45", "co-256" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-131" }, { "code": "N19", "group": "RARC", "summary": "A remark code: the procedure is considered incidental to the primary procedure on the claim. It rides along with a bundling reason code and supplies the why — this service is treated as part of the main event, not a separately payable act.", "causes": [ "A minor service performed in the course of a larger one — the access, the closure, the look-around — billed as if freestanding.", "A code pair where payment policy folds the lesser service into the greater." ], "fix": [ "Work the reason code it arrived with; N19 is context, not the decision itself.", "Ask the real clinical question: was this genuinely a distinct service — separate site, separate session, separate indication — or part of doing the primary procedure properly? Only the first is worth an appeal, and only with documentation that shows the separation.", "If it was incidental, the write-off is correct. Appealing correct bundling burns credibility you will want for the wrong bundling." ], "prevent": "Coders who know which of their common services the payers treat as incidental code them right the first time. That list is short, stable, and worth keeping.", "scrubbable": false, "appealable": false, "related": [ "co-97", "co-234" ], "url": "https://medicalcodingsoftware.org/denial-codes/n19" }, { "code": "N382", "group": "RARC", "summary": "A remark code: the patient identifier is missing, incomplete, or invalid. The member ID on the claim failed the payer's check — wrong format, wrong digits, or nobody's number. It usually rides with CO-16 or PR-31 and tells you which field to fix.", "causes": [ "A mistyped member ID — a digit off, a dropped suffix, a leading letter missing.", "An old ID from before the payer reissued cards or migrated systems.", "The right ID for the wrong payer — the claim went somewhere this number means nothing." ], "fix": [ "Pull the card, re-run eligibility, and correct the identifier exactly as the payer's system has it — including any alpha prefix or member suffix the desk trimmed off.", "Resubmit as a corrected claim. This is a data fix; there is nothing to argue." ], "prevent": "Card scans beat transcription. Every hand-keyed member ID is a chance to mint this remark, and the eligibility check that would catch it costs seconds at check-in.", "scrubbable": false, "appealable": false, "related": [ "co-16", "pr-31", "ma130" ], "url": "https://medicalcodingsoftware.org/denial-codes/n382" }, { "code": "CO-256", "group": "CO", "summary": "Not payable per your managed care contract. The payer isn't citing coverage rules or coding edits — it is citing the deal you signed. Some provision of your participation agreement makes this service, in this context, not separately payable.", "causes": [ "The contract folds this service into another payment — a case rate, a per-diem, a global arrangement that already includes it.", "A contractual exclusion: the agreement lists services it will not pay this provider type for.", "The service belongs to a different arrangement under the same contract — capitated when billed fee-for-service, or vice versa." ], "fix": [ "Get the contract out and find the provision. You cannot evaluate this denial without it — and asking the payer to cite the specific section is a legitimate first move.", "If the provision was misapplied, dispute through the contract's own dispute-resolution process, citing the section. Contract disputes follow the contract's route, not the standard appeal form.", "If the contract really does say so, the write-off is yours and the patient cannot be billed. Flag it for your next contract negotiation instead." ], "prevent": "Know what your managed care contracts actually say about your top services. The provisions behind this denial were negotiable once and will be again — but only if billing tells contracting which ones are biting.", "scrubbable": false, "appealable": true, "related": [ "co-24", "co-131", "co-45" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-256" }, { "code": "PR-200", "group": "PR", "summary": "The expenses fall inside a lapse in coverage — the policy existed, but premiums weren't current when the service happened, so the plan is holding the patient responsible. Unlike a termination, a lapse can sometimes be cured after the fact.", "causes": [ "Premiums went unpaid and the coverage lapsed before the date of service.", "The patient is inside a premium grace period — marketplace plans with subsidies have a long one, and claims from its later stretch pend or deny until the premiums are paid.", "A retroactive termination for non-payment reached back past the visit." ], "fix": [ "Have the patient contact the plan about reinstatement. If they pay the back premiums inside the grace period, lapsed claims are typically reprocessed — this denial can literally undo itself.", "Verify the actual lapse dates against the date of service; payers get these wrong at the boundaries.", "If the lapse stands, the balance is the patient's. Bill promptly and plainly — the longer it sits, the more it surprises them." ], "prevent": "Eligibility checked close to the date of service, especially for marketplace coverage early in the year. A patient in month two of a grace period shows 'active' on a shallow check and becomes this denial on a deeper one.", "scrubbable": false, "appealable": false, "related": [ "pr-27", "pr-26" ], "url": "https://medicalcodingsoftware.org/denial-codes/pr-200" }, { "code": "CO-129", "group": "CO", "summary": "The prior processing information on the claim looks wrong to the payer. This shows up on resubmissions and corrected claims: the reference back to the original claim — the number, the frequency code, the story of what this submission is — doesn't add up.", "causes": [ "A corrected claim citing the wrong original claim number, or none at all.", "The wrong claim frequency code — a replacement submitted as an original, a void pointed at a claim that doesn't match.", "A resubmission racing its own original: the 'correction' arrived while the first claim was still in process." ], "fix": [ "Pull the original remittance and get its claim number exactly right — that reference is what the payer is failing to match.", "Resubmit with the correct frequency code for what you intend: replacement to change it, void to kill it, and the original claim number carried in the reference field.", "If the original is still pending, wait for it to finish before correcting it. You cannot amend a decision that hasn't been made." ], "prevent": "A corrected-claim workflow that always carries the original claim number and the right frequency code. Corrections are routine; corrections submitted as brand-new claims are how one denial becomes three.", "scrubbable": false, "appealable": false, "related": [ "co-18", "oa-18", "co-16" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-129" }, { "code": "PR-45", "group": "PR", "summary": "The charge exceeds the fee schedule or allowed amount — and unlike CO-45, the PR prefix marks the excess as the patient's. That grouping is only legitimate in specific situations, so this code deserves a suspicious read before anyone gets billed.", "causes": [ "A genuinely out-of-network claim where the plan pays its OON allowance and leaves the balance to the patient.", "A payer grouping error: an in-network claim's contractual write-off mislabeled PR — it happens, and it invites a balance bill your contract forbids.", "A service where the patient accepted charges above the allowance in writing beforehand." ], "fix": [ "Establish network status for this plan and date first. If you are in-network, the excess is a write-off no matter what the prefix says — flag the remit error to the payer and do not bill the patient for it.", "If out-of-network, check surprise-billing protections (emergency care, OON providers at in-network facilities) before billing; where they apply, the patient owes in-network cost sharing and the rest is between you and the plan.", "Where balance billing is genuinely permitted and disclosed, bill the balance — with an explanation, because this bill is the kind patients call about." ], "prevent": "Post by rule, not by prefix. A posting process that blindly bills whatever lands in PR will eventually balance-bill someone your contract or federal law says you can't — and that mistake costs more than the balance.", "scrubbable": false, "appealable": false, "related": [ "co-45", "pr-242" ], "url": "https://medicalcodingsoftware.org/denial-codes/pr-45" }, { "code": "PR-26", "group": "PR", "summary": "The expenses predate the coverage — service rendered before the policy's effective date, so the plan says it hadn't started paying for this patient yet, and the bill is theirs.", "causes": [ "The visit happened before the plan's effective date — new-job coverage that started on the first of the month after the visit, or a plan picked during enrollment that hadn't begun.", "The wrong plan year's card: the patient presented coverage that would exist soon rather than coverage that existed then.", "An effective date recorded wrongly on the payer's side." ], "fix": [ "Verify the actual effective date against the date of service. If the payer has it wrong, the patient's enrollment paperwork settles it — appeal with it.", "Check whether other coverage existed on the date of service — the previous employer's plan, COBRA that was elected, or Medicaid, whose retroactive eligibility can reach back and pay claims from before the application.", "If no coverage existed on that date, the balance is the patient's — a self-pay conversation, and better had early." ], "prevent": "Eligibility verified against the date of service, not the date of scheduling. Coverage boundaries are exactly where a week-old verification lies to you.", "scrubbable": false, "appealable": false, "related": [ "pr-27", "pr-200", "pr-31" ], "url": "https://medicalcodingsoftware.org/denial-codes/pr-26" }, { "code": "CO-55", "group": "CO", "summary": "The payer classifies the treatment as experimental, investigational, or unproven — outside what it considers established medicine, and therefore outside what it pays for. Also one of the most overturnable denials in the book, when the evidence is on your side.", "causes": [ "The service is genuinely emerging: new technology, a new application of an existing procedure, a device early in its adoption curve.", "The payer's medical policy hasn't caught up with practice — the classification reflects the policy's last review date, not the current literature.", "A coding choice (an unlisted code, an unusual pairing) made an established service look novel." ], "fix": [ "Read the payer's medical policy for the service — it names its own evidence standards, and an appeal that speaks to those standards is twice as strong.", "Build the evidence appeal: peer-reviewed outcomes, specialty-society position, FDA status where relevant, and a letter of medical necessity explaining why this treatment for this patient. Request a peer-to-peer review with a specialist in the field.", "Rule out the coding cause first — if an unlisted code triggered it and an established code fits, that is a resubmission, not a literature review." ], "prevent": "For services near the policy edge, check the payer's medical policy before scheduling and use predetermination where offered. A coverage answer in hand beats a coverage argument after the fact.", "scrubbable": false, "appealable": true, "related": [ "co-50", "co-197" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-55" }, { "code": "MA130", "group": "RARC", "summary": "Your claim is unprocessable: something on it is incomplete or invalid, and — this is the part that matters — it comes with no appeal rights, because in the payer's eyes no claim was ever properly filed. Fix it and submit fresh; do not waste an appeal on it.", "causes": [ "A required field failed validation — the same family of causes as CO-16, on Medicare claims particularly.", "An identifier that doesn't check out: NPI, member ID, a code invalid for the date of service.", "A structural problem in how the claim was assembled that the front-end edits caught." ], "fix": [ "Find the companion remark codes — they name the offending field. MA130 says 'unprocessable'; its neighbors say why.", "Correct and submit as a NEW claim. Not an appeal (there is nothing to appeal), and not a corrected claim (there is no processed original to correct).", "Move fast: an unprocessable claim generally does not stop the timely filing clock, so the deadline is running as if you had never billed." ], "prevent": "Front-end rejections and unprocessable claims deserve the same daily attention as denials. They are easier to fix and more dangerous to ignore, precisely because nothing about them pauses any deadline.", "scrubbable": true, "appealable": false, "related": [ "co-16", "n382", "co-29" ], "url": "https://medicalcodingsoftware.org/denial-codes/ma130" }, { "code": "CO-8", "group": "CO", "summary": "The procedure is inconsistent with the provider's type or specialty. The payer looked at who performed the service and what the service was, and its records say providers like this don't do things like that.", "causes": [ "The taxonomy code on the claim, or on the provider's enrollment file, doesn't support the service billed.", "The wrong rendering NPI — the service attributed to a provider whose specialty doesn't fit it, when a colleague actually performed it.", "The provider's enrollment record is stale: a new certification or added specialty that never made it to the payer's file.", "A group NPI used where the payer wanted the individual rendering provider." ], "fix": [ "Check the claim first: is the rendering NPI the person who actually performed the service? A wrong NPI is a corrected claim, not an argument.", "Compare the provider's taxonomy in NPPES and in the payer's enrollment file against the service. If the records are stale, update them — then resubmit or appeal with the corrected credentials.", "If the payer's specialty logic is simply wrong about scope of practice, appeal with licensure and certification documentation." ], "prevent": "Keep NPPES and payer enrollment records aligned with what your providers actually do — new certifications, added services, changed roles. Enrollment data ages quietly and denies loudly.", "scrubbable": false, "appealable": false, "related": [ "co-16", "pr-242" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-8" }, { "code": "CO-288", "group": "CO", "summary": "No referral on file. Different animal from prior authorization: a referral is the PCP directing the patient to you, required by gatekeeper-model plans, and the payer can't find one for this claim.", "causes": [ "The patient's HMO requires PCP referrals and nobody obtained one before the visit.", "A referral exists but expired, ran out of visits, or names a different provider or specialty.", "The referral was issued but never transmitted — it lives in the PCP's system and nowhere the payer can see." ], "fix": [ "If a referral existed, this is the easy appeal: obtain the referral record from the PCP and submit it with the claim numbers.", "If not, contact the PCP about a retroactive referral — plans vary on whether and how far back they allow it, and the PCP's cooperation decides it.", "Failing both, appeal on circumstances if they warrant (urgent need, plan's own directory error) — and note the CO grouping: without a cure, this is your write-off, not the patient's bill." ], "prevent": "Make 'does this plan require a referral, and do we have it' a scheduling question for every gatekeeper plan. The referral requirement is knowable from the eligibility response; the denial is only inevitable if nobody looks.", "scrubbable": false, "appealable": true, "related": [ "co-197", "pr-242" ], "url": "https://medicalcodingsoftware.org/denial-codes/co-288" } ]