Guides
Billing and denials, explained plainly
Evergreen guidance on NCCI edits, medically unlikely edits and reading a remittance, for working medical billers. Where a claim depends on the specific code pair or payer, we link the cited lookup page rather than stating a number that might not be yours.
Can modifier 59 bypass an MUE? No, and here is how to tell the two denials apart
Modifier 59 answers a procedure-to-procedure bundling edit. It does nothing to a medically unlikely edit, which caps the units of one code on one date. Here is how to tell which edit fired, what the MAI decides, and a worked example from the CMS table.
Read the guideM76 remark code: what a missing or invalid diagnosis denial means, and how to fix it
RARC M76 means the claim has no diagnosis, or an ICD-10 code that is invalid, not specific enough or not linked to the service line. Here is what it pairs with, how to fix it, and what our own register says about it.
CO-197 denial code: precertification needed
A practical guide to CO-197: verify authorisation facts, identify remittance detail and decide when an appeal has a real basis.
CO-50 denial code: not medically necessary
Understand CO-50, separate coverage evidence from coding errors and prepare a focused next step for a denied claim.
CO-18 denial code: duplicate claim or service
Resolve CO-18 without creating duplicate billing: compare identifiers, identify the original adjudication and use the right replacement process.
CO-11 denial code: diagnosis is inconsistent
Understand CO-11, find the diagnosis-to-service mismatch and correct a claim without guessing at clinical documentation.
Modifier 91: repeat laboratory tests
Know when modifier 91 is appropriate, what it does not mean and how to document repeated laboratory work without misusing it.
PR-1, PR-2 and PR-3 denial codes explained
A clear guide to PR adjustment codes, patient responsibility and the checks to complete before sending a balance statement.
XE, XP, XS and XU modifiers: a practical guide
Choose between XE, XP, XS and XU with a documented distinction, not a modifier habit. Learn the questions to ask before billing.
Anatomic modifiers: left, right and bilateral
Use LT, RT and bilateral billing logic carefully: establish anatomy from the record, then follow the payer's current claim instructions.
NCCI edits: a quarterly update checklist
A repeatable way to review quarterly NCCI edit updates, keep claim rules current and avoid treating an old spreadsheet as policy.
MUE lookup: what to check before billing units
A useful MUE lookup begins with the exact code, date and claim context. Learn what an MUE value can and cannot tell you.
Timely filing limits: a verification checklist
Check timely filing limits safely: identify the payer, product and deadline source before relying on an online billing table.
Corrected claim vs reconsideration request
Choose the right recovery route after a denial: learn when claim data needs correction and when a payer decision needs reconsideration.
CARC and RARC root-cause analysis guide
Turn CARC and RARC patterns into prevention work: classify denials, preserve detail and test whether the upstream fix actually works.
Denial management work queue: what to review
Evaluate a denial-management work queue by evidence, deadlines and outcomes, not by how many claims it can display.
Claim scrubber checklist: 12 questions to ask
Evaluate claim scrubbing software without marketing fog: ask about data currency, evidence, PHI handling and what each result really means.
CO-29 denial code: the time limit for filing has expired
CO-29 means the claim missed its filing deadline, and no amount of clinical documentation will overturn it on the merits. Here is when it is genuinely worth appealing, and how to stop it recurring.
Denial management software vs. outsourcing: what actually fixes the number
Percentage-fee outsourcing or flat-fee software? Compare the real economics, then scrub a claim free.
Claim scrubber software in 2026: what matters before you pick one
Most claim scrubber comparisons rank by feature checklist. Here is what actually separates a scrubber worth trusting from one that just adds a step, and where our own tool sits honestly against that bar.
Why claim denial rates are rising in 2026
Denial rates are not just a perception problem. Recent AHA and Experian Health data show why more claims are denying, why appeals are underused despite high overturn rates, and what that means for billing offices right now.
How to write a medical claim appeal letter (template)
A working template for a medical claim appeal letter, section by section, with the placeholders filled in from a real denial so you can see exactly what a reviewer needs to see.
Timely filing limits by payer: 2026 quick reference
Medicare's timely filing limit is 12 months from the date of service. Commercial and Medicaid limits vary by payer; here is what we can confirm.
PR-204 denial code: non-covered services and ABNs
PR-204 means the service is excluded from the plan entirely, not denied for lack of medical necessity. Here is how to confirm the exclusion, when an ABN changes the outcome, and when to bill the patient.
CO-45 denial code: write-off or a real appeal?
CO-45 usually means a routine contractual write-off, not an error. Here is the narrow set of circumstances where it is actually worth disputing, and why appealing the rest just wastes a filing window.
CO-97 denial code: is a bundling denial appealable?
CO-97 means a service is bundled into another procedure already paid on the claim. Sometimes that is correct and sometimes it is a missing modifier. Here is how to tell the difference before you appeal.
CO-16 denial code: fixing missing information fast
CO-16 means the claim lacks information or has a submission error, and it always arrives with a remark code that names the actual problem. Here is how to read the pair and resubmit correctly the first time.
Claim reconsideration request: how to write one a payer has to answer
How to write a claim reconsideration request a reviewer can act on: the six parts they check, the deadline to confirm first, and a CO-45 example.
Reading a remittance: turning a CARC and RARC pair into a corrective action
A remittance advice gives you a CARC and usually one or more RARCs. Here is what each one is actually telling you, how the group code decides who owes the money, and how to turn the pair into a ranked next step instead of a guess.
MUE MAI 1 vs 2 vs 3: which unit-count denials you can actually appeal
A medically unlikely edit denial is not one thing. The adjudication indicator, MAI 1, 2 or 3, decides whether reducing units, resubmitting with documentation or appealing is even possible. Getting this wrong wastes an appeal on a code that can never win one.
How NCCI PTP modifier indicators work, and when modifier 59 is actually legitimate
NCCI procedure-to-procedure edits carry a modifier indicator of 0, 1 or 9. Only indicator 1 can ever be bypassed by a modifier, and only when the two services were genuinely distinct. Here is how the check actually works.
A guide explains the mechanism. Your remittance decides the code.
Look up the exact CARC, RARC or modifier on your claim, cited to the X12 or CMS source, or scrub the claim before you send it.