Billing Rules Library
Medical Billing Rules and Coding Policies, Simplified
Start with the operational question, then verify the reviewed official source, effective date, payer policy, and claim-specific facts.
Claims and transactions
Build, validate, submit, and track professional and institutional claims.
Medical Billing Process Step by StepA reliable claim starts before the encounter. Eligibility, authorization, documentation, coding, claim edits, payer routing, remittance posting, and follow-up are one connected control system.Foundation / 18 minHow to Complete a CMS-1500 or 837P ClaimThe 837P is the standard electronic professional claim. CMS-1500 is the paper form used when an allowed paper-claim exception applies; both represent the same claim story through different formats.Intermediate / 28 minUB-04 and 837I Institutional Billing ExplainedInstitutional providers generally submit 837I transactions. CMS-1450, also called UB-04, is the paper counterpart used only when an applicable exception allows paper submission.Intermediate / 32 minMedical Claim Scrubbing Checklist Before SubmissionA clean-claim review tests whether the claim can pass format edits and whether its facts agree: person, payer, provider, service, diagnosis, setting, authorization, units, documentation, and COB.Intermediate / 16 minInsurance Eligibility Verification 270 271 ExplainedA 270 is an eligibility inquiry and a 271 is the response. The response can confirm useful coverage and benefit data, but it is not a guarantee that a specific claim will pay.Intermediate / 18 min
Coding and claim edits
Apply code sets, POS, NCCI, MUE, and distinct-service modifier rules.
ICD-10 vs CPT vs HCPCS ExplainedICD-10-CM reports diagnoses, ICD-10-PCS reports inpatient hospital procedures, CPT reports many physician and outpatient services, and HCPCS Level II reports supplies, drugs, equipment, and other services not represented in CPT.Foundation / 20 minMedicare Place of Service Codes ExplainedPOS codes identify the service setting on professional claims. The correct code depends on the actual location and payer rules, and can change payment and coverage edits.Intermediate / 20 minHow Medicare NCCI PTP Edits WorkA Medicare NCCI PTP edit identifies code pairs that generally should not be paid together for the same beneficiary and date. The Column Two code denies unless the edit permits a modifier and the clinical facts support a valid exception.Advanced / 28 minMedicare MUE Values and Unit Denials ExplainedAn MUE is a Medicare unit-of-service edit for a code, provider, beneficiary, and date. The adjudication indicator determines how the edit is applied and whether records may support review above the value.Advanced / 26 minModifier 59 vs XE XP XS XU for NCCI EditsModifier 59 is a last-resort distinct procedural service modifier. CMS directs use of a more specific XE, XP, XS, or XU modifier when it accurately describes the documented relationship.Advanced / 24 min
Denials and payment
Read remittance, choose the right resolution route, and preserve appeal rights.
CARC and RARC Denial Codes ExplainedThe group code assigns the adjustment category, the CARC gives the general reason, and RARCs add detail. Read the full combination at claim and line level before deciding who owns the balance or what to do next.Intermediate / 25 minShould I Correct, Reopen, or Appeal a Denied Medicare Claim?Correct inaccurate claim data through the allowed correction channel. Use a reopening for eligible minor errors or omissions after determination. Appeal when you dispute an initial coverage or payment determination and have supporting facts.Intermediate / 22 minHow to Appeal an Original Medicare Claim DenialOriginal Medicare has five appeal levels. The first is MAC redetermination, generally requested within 120 days of receiving the initial determination; later levels have different deadlines, amount-in-controversy rules, and filing destinations.Advanced / 30 minDoes a Medicare Fee Schedule Amount Mean a Service Is Covered?No. A fee schedule amount is a payment reference for a code and context. It does not prove that the item or service is covered, reasonable and necessary, correctly coded, authorized, or payable on a specific claim.Foundation / 14 min
Medicare compliance
Manage filing, authorization, payer order, notices, enrollment, and records.
Medicare Timely Filing Limit and ExceptionsOriginal Medicare generally requires a claim to reach the correct contractor no later than 12 months, or one calendar year, after the applicable date of service. A timely-filing denial is generally not an initial determination and is not appealable.Intermediate / 18 minMedical Prior Authorization Process and Denial ChecklistAn approval number alone is not enough. The authorization must match the patient, payer, plan, provider, service, setting, quantity, and service dates that appear on the claim.Intermediate / 24 minWho Pays First: Medicare Secondary Payer RulesMedicare is secondary when federal MSP rules assign primary responsibility to another plan or coverage. Providers must determine payer order before billing and include required primary-payer adjudication information on a secondary claim.Advanced / 30 minMedicare ABN Rules and GA GY GZ GX ModifiersAn ABN is a specific Original Medicare notice used before furnishing certain items or services expected to deny. The notice and claim modifier must match the reason, timing, and liability facts; a modifier does not cure an invalid or late notice.Advanced / 28 minNPI Taxonomy and PECOS Claim Denials ExplainedAn NPI identifies a provider but does not by itself establish Medicare billing privileges. Enrollment, reassignment, specialty or taxonomy, practice location, and ordering or referring eligibility may also control processing.Intermediate / 22 minMedical Necessity Documentation for Insurance ClaimsA claim field is not a substitute for the medical record. Documentation should show what was ordered, why it was reasonable and necessary, what was furnished, who performed or ordered it, and how the billed code, level, units, and frequency follow from those facts.Intermediate / 25 minHIPAA Rules for Medical Billing StaffBilling records can contain protected health information. Use only approved systems and authorized disclosures, limit access to the task, and never paste patient data into public research or consumer AI tools.Foundation / 18 min
DME reimbursement
Connect benefit, coverage, documentation, delivery, rental, replacement, and fee logic.
How Medicare DME Billing and Reimbursement WorksDME reimbursement requires more than a code: the supplier, beneficiary, item, setting, order, medical record, delivery, modifier, rental or purchase sequence, and applicable policy must align.Intermediate / 26 minDoes a Medicare Fee Schedule Amount Mean a Service Is Covered?No. A fee schedule amount is a payment reference for a code and context. It does not prove that the item or service is covered, reasonable and necessary, correctly coded, authorized, or payable on a specific claim.Foundation / 14 minMedical Necessity Documentation for Insurance ClaimsA claim field is not a substitute for the medical record. Documentation should show what was ordered, why it was reasonable and necessary, what was furnished, who performed or ordered it, and how the billed code, level, units, and frequency follow from those facts.Intermediate / 25 min