Medicare Part D
Medicare prescription drug coverage delivered through stand-alone PDPs or MA-PD plans.
1 min read · Last reviewed May 23, 2026
At a glance
- Category
- Payer
- Primary sources
- 1
- Workspace handoff
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Where this comes up
Front-office and billing both hit this term — eligibility before the visit, prior auth before the procedure, contract terms during fee-schedule negotiation, and credentialing whenever a new provider joins or a payer roster lapses. Misses here become denials downstream.
Full definition
What it is in practice
CMS Part D is a private-plan benefit with a CMS-defined standard formulary structure. The coverage gap closed under the Inflation Reduction Act in 2025; out-of-pocket caps continue tightening.
How it shows up in your practice
Prescribers should screen against the Preclusion List monthly to avoid Part D point-of-sale denials. ePrescribing of controlled substances follows DEA EPCS rules.
Sources
- CMS — Medicare Part Dhttps://www.cms.gov/medicare/coverage/prescription-drug-coverage
Look up Part D rules in Ask D3
Open ask d3 →Related terms
- PayerMedicare Part C (Medicare Advantage)Medicare benefits delivered through private health plans contracted with CMS, often with additional benefits and a managed-care structure.
- EnrollmentPreclusion ListCMS list of prescribers and providers whose claims and prescriptions are denied payment by Medicare Advantage and Part D.
- DocumentationE-Prescribing of Controlled Substances (EPCS)DEA-regulated electronic prescribing of Schedule II-V controlled substances.
- PayerFormularyA health plan's list of covered drugs, typically organized by tier with associated cost-sharing.
D3rx is a healthcare-billing and compliance research aid maintained by D3rx Inc. Articles are drafted by an LLM (Anthropic Claude) against primary HHS, OCR, CMS, eCFR, NIST, and state-regulator publications, and reviewed for restraint and source fidelity by the D3rx team.
Reviewer status: a named credentialed reviewer (CHC, CHPC, or healthcare attorney) is being engaged. Until that engagement is finalized, this page does not claim credentialed review.
Related across the archive
- GlossaryFormularyA health plan's list of covered drugs, typically organized by tier with associated cost-sharing.
- GlossaryMedicare Part C (Medicare Advantage)Medicare benefits delivered through private health plans contracted with CMS, often with additional benefits and a managed-care structure.
- GlossaryE-Prescribing of Controlled Substances (EPCS)DEA-regulated electronic prescribing of Schedule II-V controlled substances.
- GlossaryPreclusion ListCMS list of prescribers and providers whose claims and prescriptions are denied payment by Medicare Advantage and Part D.
- GlossaryStep TherapyA payer requirement that less expensive drug or service options be tried before more expensive alternatives are covered.
- ComplianceOIG LEIE Monthly Exclusion Screening: Process + Audit-Ready LogsMonthly OIG LEIE and SAM.gov exclusion screening for every workforce member and vendor: the workflow, the log fields auditors require, and the escalation path.
- CompliancePECOS Provider Enrollment Verification (2026) — Quarterly ChecklistQuarterly PECOS provider enrollment verification workflow: who to check, the exact lookup steps, the audit log columns, and the revalidation escalation path.
- RegulationMLN: 'Incident To' Services in Medicare Part BReference to Medicare's incident-to billing rules permitting auxiliary personnel to furnish services billed under the physician's NPI, with strict supervision and treatment-plan requirements.
This glossary entry is a research aid for billing and compliance staff. It does not provide legal, medical, or financial advice and does not replace counsel. References cited link to primary sources at HHS, OCR, CMS, eCFR, NIST, and the relevant payer or industry body.