CMS Routine Costs in Clinical Trials Coverage Policy Updated for 2026 (NCD 1)

CMS has issued a modification to National Coverage Determination (NCD) 1, governing Medicare coverage of routine costs in qualifying clinical trials. This update clarifies which items and services Medicare will—and will not—pay for when a beneficiary participates in an approved clinical trial, and it touches virtually every Medicare benefit category across nearly every clinical specialty. Billing teams that manage claims for patients enrolled in research studies need to understand exactly where coverage begins and ends under this policy.

What CMS NCD 1 Covers: Routine Costs in Qualifying Clinical Trials

The Centers for Medicare & Medicaid Services established its clinical trial coverage policy under NCD 1, with the foundational rule taking effect July 9, 2007. The 2026 modification affirms and clarifies that Medicare covers the routine costs of qualifying clinical trials as well as reasonable and necessary items and services used to diagnose and treat complications arising from participation in any clinical trial.

The word "routine" is doing significant work here. Under NCD 1, routine costs are defined as items and services that are otherwise generally available to Medicare beneficiaries—meaning three conditions must be met simultaneously:

1. A Medicare benefit category exists for the item or service
2. The item or service is not statutorily excluded from Medicare coverage
3. There is no existing national non-coverage decision barring the item or service

If all three conditions are satisfied, and the item or service is provided in either the experimental arm or the control arm of a clinical trial, it can qualify as a routine cost and be billed to Medicare.

What Medicare Will NOT Pay For in a Clinical Trial

This is where most billing errors originate. NCD 1 explicitly carves out three categories of items and services that are never covered as routine clinical trial costs, even if the patient is a Medicare beneficiary and even if the item would otherwise be covered in a non-trial context.

1. The investigational item or service itself
The drug, device, or procedure being studied is excluded from Medicare coverage under this policy—unless that item or service has separate Medicare coverage outside the context of the clinical trial. If a novel chemotherapy agent has no independent CMS coverage determination approving it, Medicare will not pay for it simply because it appears in a trial.

2. Items and services that exist solely for data collection
If a protocol requires, say, monthly CT scans for a condition that would clinically require only a single scan, those additional scans are not covered. The key test is whether the item or service is being used in the direct clinical management of the patient. If the answer is no—if it exists purely to satisfy research data requirements—it is excluded.

3. Items and services provided free-of-charge by the research sponsor
If the trial sponsor customarily provides certain items or services at no cost to any enrollee, Medicare will not pay for those same items. This prevents double billing and reflects the longstanding Medicare principle against billing for costs that are not actually incurred by the beneficiary or provider.

The Benefit Category Scope: Why This Policy Touches Every Specialty

The breadth of NCD 1 is striking. CMS explicitly lists applicable benefit categories that span the entirety of Medicare-covered services, including—but not limited to—physician services, inpatient and outpatient hospital services, diagnostic laboratory tests, diagnostic X-ray, drugs and biologicals, durable medical equipment, home health services, skilled nursing facility care, ambulatory surgical center facility services, ambulance services, physical and occupational therapy, speech-language pathology, partial hospitalization, hospice care, transplantation services, and oral anticancer and antiemetic drugs.

This means any provider type that sees Medicare patients enrolled in clinical trials—from large academic medical centers to small rural health clinics—must apply NCD 1 correctly. The policy also covers benefit categories such as ESRD-related services (institutional dialysis, home dialysis supplies, erythropoietin), prosthetics and orthotics, and chiropractic services.

CMS notes explicitly that the listed benefit categories may not be exhaustive. When in doubt, the three-part test above (benefit category exists, not statutorily excluded, no national non-coverage decision) is the operative standard.

Medical Necessity and Clinical Trial Qualification Requirements

Not every clinical trial automatically triggers NCD 1 protections. The trial itself must be a "qualifying" clinical trial. While the full qualification criteria appear in the untruncated policy text and associated guidance, billing teams should confirm that any trial for which they are submitting routine cost claims meets CMS's qualifying criteria before billing. Submitting routine cost claims against a non-qualifying trial is a compliance risk.

Separately, items and services billed as routine costs must independently meet Medicare's medical necessity standards. The clinical trial context does not override the requirement that each line item be reasonable and necessary for the diagnosis or treatment of the patient's condition. A service that fails medical necessity review does not become covered simply because it was furnished during a clinical trial.

Affected Codes

This policy does not list specific CPT, HCPCS, or ICD-10 codes. Coverage under NCD 1 is determined by benefit category eligibility and the routine cost definition rather than a discrete code list. Claims should be billed using the standard CPT or HCPCS codes that would apply in a non-trial setting, provided the item or service meets the routine cost definition above.

If your billing system requires a policy-specific code flag, consult your Medicare Administrative Contractor (MAC) for local guidance on claims submission requirements for clinical trial billing.

What Your Billing Team Should Do