Coordination of benefits (COB)

What Is a Claim Denial?

A claim denial is a payer's decision, after adjudication, to refuse payment in whole or in part — and it is not the same thing as a rejection.

Updated July 16, 2026 · 8 min read

Denials & Appeals

Why Claims Get Denied

Denials cluster into a small number of recurring reasons — eligibility, authorization, medical necessity, coding, filing, and coverage order — each pointing back to a different step.

Updated July 16, 2026 · 8 min read

Denials & Appeals

Reading a Denial: Codes, Group Codes, and the Remittance

A denial arrives as standardized codes on the remittance advice. Reading them — the adjustment reason, the group code, and the remark — is what tells you what to do next.

Updated July 16, 2026 · 8 min read

Denials & Appeals

Appealing a Denial: When, What, and How Long You Have

An appeal argues that the payer's decision was wrong. Knowing when to appeal rather than correct, and what evidence answers the reason given, is most of the outcome.

Updated July 16, 2026 · 8 min read

Denials & Appeals

Preventing Denials: The Controls That Work Upstream

Denials are produced by a process, and the controls that stop them sit before the claim is sent — in registration, authorization, documentation, and the feedback loop that closes.

Updated July 16, 2026 · 7 min read

Payments & Posting

Secondary Billing and Coordination of Benefits

When a patient has more than one plan, the balance after the primary goes to the next — and it can only go there if the primary was posted line by line.

Updated July 16, 2026 · 6 min read

Eligibility verification

What Is Eligibility Verification?

Eligibility verification confirms, before or at the visit, that a patient's coverage is active for the planned care — the first assertion on every future claim and the cheapest place to catch a coverage problem.

Updated July 18, 2026 · 4 min read

Eligibility verification

Eligibility vs. Benefit Verification

Eligibility verification confirms that coverage is active; benefit verification establishes what that coverage pays for a specific service. They are run together, but they are different assertions that fail in different ways.

Updated July 18, 2026 · 4 min read

Eligibility verification

Reading an Eligibility Response

An eligibility response answers more than “active or not.” Reading it well means finding the plan and dates first, then benefits and cost share, then the requirements — and knowing which parts are facts and which are estimates.

Updated July 18, 2026 · 3 min read

Eligibility verification

Confirming Active Coverage and Effective Dates

Confirming active coverage means verifying that a plan was in force on the specific date of service by reading the effective and termination dates in the eligibility response — not simply checking whether coverage is active on the day the check is run.

Updated July 18, 2026 · 8 min read

Eligibility verification

Identifying Primary and Secondary Coverage

When a patient has more than one health plan, coordination-of-benefits (COB) rules — not patient or staff preference — decide which plan is primary (billed first) and which is secondary. Identifying that order at registration matters because billing the wrong plan primary can trigger a denial even when the diagnosis and procedure coding are correct.

In practice

Sources

Referenced in the Knowledge Base

What Is a Claim Denial?

Why Claims Get Denied

Reading a Denial: Codes, Group Codes, and the Remittance

Appealing a Denial: When, What, and How Long You Have

Preventing Denials: The Controls That Work Upstream

Secondary Billing and Coordination of Benefits

What Is Eligibility Verification?

Eligibility vs. Benefit Verification

Reading an Eligibility Response

Confirming Active Coverage and Effective Dates

Identifying Primary and Secondary Coverage

Verifying Medicare Eligibility

Verifying Medicaid Eligibility

Eligibility-Related Denials and Their Causes

Building a Front-Desk Eligibility Workflow

Verifying Secondary and Tertiary Coverage

Registration Data Quality and Eligibility

Re-Verifying Recurring Patients

Measuring Eligibility Verification Performance

Eligibility Verification Tools and Automation

Precertification, predetermination, and prior authorization

Submitting a prior authorization request

Retroactive and urgent authorizations

Prior authorization under Medicaid

How Medicare is structured (Parts A, B, C, D)

Medicare Part A billing

Medicare Part B billing

Medicare Advantage (Part C) billing

The Medicare Beneficiary Identifier (MBI)

Medicare fee schedules explained

Medicare Secondary Payer (MSP) billing

Medicare timely filing

Medicare telehealth billing

Medicare overpayments and recoupment

Reading the Medicare remittance and MSN

Common Medicare billing denials

How Medicaid works

Medicaid vs. Medicare

Fee-for-service vs. managed Medicaid

Medicaid managed care organizations

Medicaid eligibility categories

Verifying Medicaid coverage

The federal-state structure of Medicaid

Medicaid fee schedules and reimbursement

Medicaid as payer of last resort

Medicaid timely filing

Medicaid prior authorization

Dual-eligible beneficiaries

Medicaid crossover claims

Medicaid and CHIP

Medicaid third-party liability

Medicaid claim submission basics

Common Medicaid billing denials

State Medicaid program variation

Behavioral health billing overview

Psychotherapy time-based billing

Substance use disorder billing

Medication-assisted treatment billing

Behavioral health eligibility and carve-outs

Collaborative care model billing

Behavioral health documentation requirements

Billing intensive outpatient and PHP

Behavioral health under Medicaid

Behavioral health under Medicare

Confidentiality and 42 CFR Part 2

Common behavioral health denials

Measuring the behavioral health revenue cycle

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