AR Billing Glossary

Plain-English definitions of the acronyms (like CARC, RARC, ERA and EOB) and terms used across AR Guide — written for new AR staff. Search by term, acronym or keyword.

47 terms · 5 categories

8

837Transactions: The standard electronic claim transaction — the file format in which professional (837P), institutional (837I) and dental (837D) claims travel from provider to payer.
835Transactions: The standard electronic remittance advice transaction — the payer's electronic explanation of how it paid (or denied) your claims. The 835 is the ERA.

A

AppealAR workflow: A formal request to a payer to reconsider a claim decision. Appeals have deadlines and required evidence — triage the denial first, then appeal with the documentation that answers the payer's stated reason.
ARAccounts ReceivableAR workflow: The money owed to the practice for services rendered — the work queue of unpaid and denied claims. 'Working AR' is following up on those claims.

B

BCBSBlue Cross Blue ShieldPayer admin: A federation of independent, state-based insurance companies. Each BCBS company sets its own policies and has its own contacts — a BCBS member ID prefix identifies the likely company, but state/plan rules still vary.

C

CARCClaim Adjustment Reason CodeCodes: The standardized code a payer attaches to a claim line to say WHY it was adjusted or denied (e.g. 29 = the time limit for filing has expired). CARCs are published by ASC X12 and are the same across all payers — the payer's story, in one code.
Claim Status Inquiry276/277Transactions: The standard electronic transactions for asking a payer the status of a claim (276) and receiving the response (277). Most provider portals and clearinghouses let you run these without knowing the transaction numbers.
CARC/RARC PairCodes: The combination of a Claim Adjustment Reason Code and a Remittance Advice Remark Code on a claim line. The CARC says why, the RARC says more. AR Guide always reads them together — the pair, not the CARC alone, tells you the right next step.
Clean ClaimBilling: A claim that can be processed without additional information from the provider — no missing data, no conflicting codes, no attachments needed. The goal of front-end edits is to get claims clean before submission.
ClearinghousePayer admin: A vendor that receives claims from providers, converts them to the payer's required format, and transmits them — returning acknowledgements and reject reports. Clearinghouse reports are proof of timely submission in timely-filing appeals.
Claim AcknowledgementTransactions: The transaction (999 / 277CA) a clearinghouse or payer sends to confirm a claim was received and whether it passed front-end edits. A rejected claim is not denied — it was never accepted. Reconciliation of acknowledgements is the first line of defense against timely-filing problems.
CPTCurrent Procedural TerminologyCodes: The AMA's code set describing medical procedures and services. CPT codes are the language of professional claims — the code, its modifiers and the diagnosis must all agree.
Corrected ClaimBilling: A resubmission of a processed claim with a correction, submitted with frequency code 7. Corrected claims are not new claims — most payers count the original filing date for timely-filing purposes.
Contractual AdjustmentBilling: The difference between what was billed and what the contract says the payer owes (group code CO). A contractual write-off is correct — it is what the agreement requires, not a loss.
COBCoordination of BenefitsAR workflow: The rules that decide which insurance pays first when a patient has more than one coverage. A COB denial usually means the claim belongs to another payer first — a routing problem, not a service problem.
CredentialingPayer admin: The process of a payer verifying a provider's qualifications, license and network participation before they can bill. A credentialing denial means the provider or facility is not set up in the payer's system — it is an enrollment issue, not a claim issue.
CMSCenters for Medicare & Medicaid ServicesPayer admin: The federal agency that runs Medicare and oversees Medicaid. CMS sets the standards many payers copy (e.g. clean-claim timing) and publishes the code lists Medicare uses.
Clean Claim TimingPayer admin: The federal standard (and state prompt-pay laws built on it) requiring payers to pay or deny clean claims within a set number of days — often 30 days for electronic claims. A claim sitting past the required window without a decision may itself be appealable.

D

DenialAR workflow: A payer's refusal to pay a claim (or a claim line) for a stated reason. Denials are not all equal: some are fixable data problems, some are documentation requests, some are legitimate appeals, and some are correct decisions. Triage before you act.
DOSDate of ServiceBilling: The date (or date range) the service was performed. Eligibility and coverage are verified for the exact DOS — never 'today'.

E

ERAElectronic Remittance AdviceTransactions: The electronic version of the explanation of benefits (the 835 transaction). The ERA is where you read the group code, CARC and RARC for every claim line — the first map for any denial.
EOBExplanation of BenefitsTransactions: The paper explanation a payer sends describing how a claim was processed. Contains the same adjustment codes as the ERA but on paper. 'The EOB says' and 'the ERA says' mean the same thing in different formats.
Eligibility Inquiry270/271Transactions: The standard electronic transactions for asking a payer whether a patient has coverage for a date of service (270) and receiving the response (271). 'Verify eligibility' means running a 270/271 or the payer's portal equivalent.
EDIElectronic Data InterchangeTransactions: The structured electronic format used to send claims, eligibility checks and other transactions between providers, clearinghouses and payers (e.g. the 837 claim, 835 remittance). 'Sending EDI' usually means submitting claims through a clearinghouse in the standard format.
ERA/EOB LineTransactions: One service line on a remittance advice, carrying its own group code, CARC and RARC. Two lines on the same claim can have different reasons — read each line, not just the claim total.

F

Frequency CodeBilling: A code on the claim that says what type of submission it is: 1 = original, 7 = replacement/corrected claim, 8 = void. Filing a correction as a new claim (frequency 1) is how duplicates are born.
FEPFederal Employee ProgramPayer admin: The BCBS program that insures federal employees. FEP member IDs start with R and have their own contact lines and rules — distinct from commercial BCBS plans.

G

Group CodeCodes: The one-letter code on an ERA/EOB that classifies who is responsible for the adjustment: CO (contractual obligation), PR (patient responsibility), OA (other adjustment), PI (payer initiated), or CR (corrected resubmission, historical). Read the group code together with the CARC — the pair tells you the story.

H

HCPCSHealthcare Common Procedure Coding SystemCodes: The code set used for services and supplies not covered by CPT (Level II codes, e.g. durable medical equipment). Claims can carry CPT and HCPCS codes on different lines.

I

ICD-10International Classification of Diseases, 10th RevisionCodes: The diagnosis code set used on claims. 'The diagnosis does not support the service' means the ICD-10 code submitted does not justify the procedure — a common coding denial.

M

ModifierCodes: A two-character code appended to a CPT/HCPCS code to say the service was altered (e.g. 25 — significant, separately identifiable E/M). Modifier denials mean the code-plus-modifier combination was not valid or was inconsistent.
MedicarePayer admin: The federal health insurance program for people 65+ and certain younger people with disabilities. Medicare has its own code set (HCPCS), its own contractors, and its own appeal levels — a different world from commercial claims.
MedicaidPayer admin: The joint federal-state program covering low-income individuals. Medicaid is administered state by state — deadlines, contacts and rules are state-specific, and managed-care plans (e.g. STAR, Medi-Cal managed care) add another layer.

N

NPINational Provider IdentifierPayer admin: The 10-digit standard identifier for providers and organizations used on claims. Every claim line needs the right NPI — billing NPI, rendering NPI and taxonomy codes must all match the payer's records.

P

Prior AuthorizationPayer admin: A payer requirement to approve a service before it is performed. Also called preauthorization, precertification, or pre-service review depending on the payer. An authorization denial means the payer has no valid, timely approval on file.
Payer IDPayer admin: The identifier a payer uses to route electronic claims — one payer can have several (one per line of business, state or plan). Using the wrong payer ID is a common cause of claims landing with the wrong plan. Payer IDs are state/plan-specific; never assume one works nationwide.
Patient ResponsibilityBilling: The portion of a claim the patient owes per the plan — deductible, coinsurance, copay, or non-covered amounts (group code PR). Bill the patient only after confirming the amount is the patient's responsibility under the plan.
Primary / Secondary InsuranceAR workflow: The order in which multiple plans pay. The primary pays first up to its allowance; the secondary pays what remains, up to its own limits. Billing the wrong order invites a COB denial and a payment delay.
PHIProtected Health InformationPayer admin: Individually identifiable health information — patient names, member IDs, dates of birth, claim numbers. AR Guide does not collect or store PHI; your own AR work should treat it with the same care.

R

RARCRemittance Advice Remark CodeCodes: A standardized remark code that adds context to a CARC — usually an explanation of what information is needed or why a payment changed. RARCs are supplemental (they explain a CARC) or informational (alerts prefixed with 'Alert:').
Revenue CodeCodes: The facility code on institutional claims that identifies the department/type of service (e.g. 450 — emergency room). A revenue code mismatch means the revenue code and procedure code disagreed.
ReconsiderationAR workflow: A payer's informal re-review of a claim — often faster than a formal appeal and required before one. Many payers expect a reconsideration (or 'claim review') before the formal appeal level.

T

Timely FilingAR workflow: The deadline by which a payer requires a claim (or corrected claim) to be submitted. Deadlines are payer-, plan- and state-specific and are measured from different events (date of service, discharge, prior denial). AR Guide does not publish deadlines — verify each payer's with the payer.
TFLTimely Filing LimitAR workflow: The timely-filing deadline — the shorthand used in payer tables and AR notes for 'how long do we have to file this'.
Tax ID / TINTaxpayer Identification NumberPayer admin: The practice's federal tax identification number used for enrollment, claims and payment. Payers verify the Tax ID along with the NPI when you call — have both ready.

V

VerificationAR workflow: The act of confirming a fact against an authoritative source — eligibility against the payer's system, a contact number against the official page, a deadline against the contract. AR Guide's core rule: verified and sourced, or not published.

W

Write-OffAR workflow: Removing a balance from accounts receivable — either contractually (the payer paid per the contract) or as a business decision. A write-off should always be a deliberate decision, not the default answer to a denial.