The Medical Billing & RCM Glossary: 25 Key Terms Explained

Revenue cycle management has its own language. Whether you bill in-house or outsource it, knowing these terms helps you read your reports, ask better questions, and catch problems early. Here are the terms practices ask us about most — in plain English.

Claims & coding

Clean claim — A claim with no errors that passes payer edits and is accepted on the first try. A high clean-claim rate is the foundation of getting paid fast.

Claim scrubbing — Automated checking of a claim for errors (codes, modifiers, eligibility, medical necessity) before it goes to the payer.

CPT code — Current Procedural Terminology code describing the service or procedure performed.

ICD-10 code — Diagnosis code that explains why a service was medically necessary.

HCPCS — Codes for items and services not covered by CPT, such as supplies, drugs, and equipment.

Modifier — A two-character add-on to a code that gives the payer extra context (e.g., a service was distinct or bilateral).

Clearinghouse — A service that checks, formats, and routes electronic claims between providers and payers.

Money & accounts receivable

RCM (Revenue Cycle Management) — The entire financial process of a patient encounter, from scheduling and eligibility through coding, billing, and final payment.

Accounts Receivable (AR) — Money owed to the practice for services already provided but not yet paid.

Days in AR — The average number of days it takes to collect payment. Lower is better; rising days in AR signal collection problems.

Allowed amount — The maximum a payer will reimburse for a service under the contract, regardless of what was billed.

Write-off / adjustment — The difference between the billed amount and the allowed amount that the practice cannot collect.

Copay, coinsurance & deductible — The three forms of patient responsibility: a fixed visit fee, a percentage share, and the amount a patient pays before insurance begins covering costs.

EOB vs. ERA — An Explanation of Benefits is the payer’s statement of how a claim was processed; an ERA is its electronic version used to post payments automatically.

Net collection rate — The percentage of collectible revenue you actually collected — a key measure of billing health.

Denials, process & compliance

Denial — A claim the payer refuses to pay. Denials are often preventable and frequently appealable.

CARC / RARC — Claim Adjustment Reason Codes and Remittance Advice Remark Codes: the standardized codes payers use to explain why a claim was adjusted or denied.

Eligibility verification — Confirming a patient’s active coverage and benefits before the visit to prevent front-end denials.

Prior authorization — Payer approval required before certain services; missing it is a common denial cause.

Credentialing — Enrolling a provider with payers so they can bill and be reimbursed in-network.

CAQH — The central profile most payers use during credentialing; keeping it current prevents enrollment delays.

NPI — National Provider Identifier, the unique number identifying a provider on claims.

Payment posting — Recording payments and adjustments against claims, and flagging underpayments for follow-up.

First-pass resolution rate — The percentage of claims paid on the first submission without rework.

Underpayment — When a payer pays less than the contracted allowed amount — recoverable revenue many practices never chase.

Not sure where your revenue cycle is leaking? A free account review from RCM Billing Solutions can pinpoint it — and show you exactly how to fix it.