TL;DR: The Centers for Medicare & Medicaid Services modified NCD 1, its national coverage determination governing routine costs in clinical trials, with an effective date of January 9, 2026. Here's what billing teams need to know.
This CMS clinical trials coverage policy has broad reach. It touches nearly every Medicare benefit category — from inpatient hospital services and durable medical equipment to drugs and biologicals, home health, and skilled nursing facility stays. The policy does not list specific CPT or HCPCS codes because it applies across virtually all service types. Clinical trials billing under NCD 1 in the NCD Medicare system requires your team to understand exactly what counts as a "routine cost" and what doesn't — because that line determines what gets reimbursed and what triggers a claim denial.
Quick-Reference Table
| Field | Detail |
|---|---|
| Payer | CMS |
| Policy | Routine Costs in Clinical Trials |
| Policy Code | NCD 1 |
| Change Type | Modified |
| Effective Date | January 9, 2026 |
| Impact Level | High |
| Specialties Affected | All specialties — oncology, cardiology, neurology, primary care, DME, home health, SNF, ASC, and more |
| Key Action | Audit your clinical trial billing workflows before January 9, 2026 to confirm you're separating routine costs from investigational items and data-only services |
CMS Clinical Trials Coverage Criteria and Medical Necessity Requirements 2026
NCD 1 is the National Coverage Determination governing Medicare coverage of routine costs in qualifying clinical trials. The foundational rule hasn't changed: Medicare covers routine costs for items and services furnished on or after July 9, 2007. The January 9, 2026 modification updates how CMS frames and documents this coverage policy — so your billing team needs to re-read the criteria, not assume nothing changed.
The medical necessity standard here is specific. CMS covers routine clinical trial costs when three conditions are met: a Medicare benefit category exists for the item or service, the item or service isn't statutorily excluded, and no national non-coverage decision applies. If all three conditions are satisfied, the item or service qualifies as a routine cost — regardless of whether the patient is in the experimental arm or the control arm.
This matters because whether a clinical trial is covered under Medicare doesn't mean every cost of that trial is covered. CMS makes a sharp distinction between routine costs and investigational costs. Getting that distinction wrong is the fastest route to a claim denial.
What Counts as a Routine Cost
Routine costs include items and services the patient would typically receive outside of a clinical trial. Think conventional evaluation and management visits, standard lab work, imaging that would be ordered anyway, and drugs that are already covered under a Medicare benefit. These are billable in the normal way — you submit them using the applicable codes for those services.
Routine costs also include items and services needed to administer an investigational item (even if that item itself isn't covered), services required for the clinically appropriate monitoring of trial effects, and services needed to prevent, diagnose, or treat complications from trial participation. This last category is important. Even if a patient develops an adverse reaction from an investigational drug, the treatment of that complication is a covered routine cost.
What Doesn't Qualify as a Routine Cost
Three categories are excluded — and your billing team should memorize them:
| # | Covered Indication |
|---|---|
| 1 | The investigational item or service itself. The drug or device being tested isn't a routine cost. It's not billed to Medicare unless it happens to have separate coverage outside the trial. |
| 2 | Services provided solely for data collection. If a monthly CT scan is ordered only because the research protocol requires it — not because the patient's clinical condition warrants it — that CT scan is not a routine cost. A patient whose condition would normally require one scan can't be billed for four scans just because the trial protocol demands monthly imaging. |
| 3 | Items and services the research sponsor provides free of charge. If the sponsor covers it for all enrollees, Medicare doesn't. |
The medical necessity test for clinical trial billing runs parallel to the standard Medicare test. A service must be clinically appropriate for the patient's condition — not just required by the protocol.
CMS Clinical Trials Billing Exclusions and Non-Covered Indications
The coverage policy draws clear lines around three non-covered categories. Understanding them protects your reimbursement — and keeps your denial rate down.
The investigational item itself. This is the thing being tested — the new drug, the novel device, the experimental procedure. Medicare doesn't cover it under NCD 1. If a sponsor is providing it free, it also can't be billed to Medicare. The only exception is if that item has independent Medicare coverage outside the trial — for example, a drug that's already on the covered formulary being tested in a new indication.
Data-only services. This is where billing errors concentrate. A research protocol often requires testing and monitoring far beyond what's clinically necessary for the patient. Those additional services — ordered purely to satisfy data collection needs — are not covered. The example CMS uses is instructive: monthly CT scans for a condition that would normally require only a single scan. Billing those scans to Medicare is a compliance risk, not a billing shortcut.
Sponsor-covered items. If the research sponsor pays for it, Medicare doesn't. Document what the sponsor covers. If you don't have that documentation, get it before you bill.
Coverage Indications at a Glance
| Indication | Status | Relevant Codes | Notes |
|---|---|---|---|
| Routine items/services in experimental arm of qualifying trial | Covered | Applicable codes for each service type | Must meet standard Medicare benefit category, exclusion, and NCD criteria |
| Routine items/services in control arm of qualifying trial | Covered | Applicable codes for each service type | Same three-part test applies |
| Items needed to administer investigational item or service | Covered | Applicable codes for each service type | Covered even if investigational item itself is not |
| Clinically appropriate monitoring of trial effects | Covered | Applicable codes for each service type | Must be clinically warranted, not protocol-only |
| Treatment of complications from trial participation | Covered | Applicable codes for each service type | Applies to all clinical trials, not just qualifying ones |
| The investigational item or service itself | Not Covered | N/A | Exception if separately covered outside the trial |
| Services provided solely for data collection | Not Covered | N/A | Protocol-required imaging, labs not clinically indicated |
| Items/services provided free by research sponsor | Not Covered | N/A | Must document sponsor-covered items |
CMS Clinical Trials Billing Guidelines and Action Items 2026
The January 9, 2026 effective date means you have a narrow window. Use it.
| # | Action Item |
|---|---|
| 1 | Audit every active clinical trial in your system before January 9, 2026. Pull a list of patients currently enrolled in trials. Confirm your team has documented which services are routine costs and which are investigational or data-only. That documentation is your first line of defense if CMS audits a claim. |
| 2 | Get sponsor coverage documentation in writing. For every active trial, confirm what the sponsor provides free of charge to all enrollees. Request a written list. This prevents you from billing Medicare for items already covered by the sponsor — which is a direct compliance violation, not just a billing error. |
| 3 | Apply the three-part test to every service before it's billed. The service needs a Medicare benefit category. It can't be statutorily excluded. It can't be subject to a national non-coverage decision. Train your billing team to run this check on any service associated with a clinical trial encounter. |
| 4 | Flag protocol-required services that exceed clinical necessity. Work with your clinical staff to identify services the protocol demands beyond what the patient's condition warrants. Those services are not routine costs. They shouldn't be on the claim. If your charge capture system doesn't distinguish between clinically-driven and protocol-driven orders, fix that workflow now. |
| 5 | Review your charge capture across all affected benefit categories. NCD 1 touches virtually every Medicare benefit category — inpatient, outpatient, home health, DME, SNF, ASC, drugs and biologicals, lab, imaging, and more. Clinical trials billing isn't siloed to one department. Talk to your charge capture team, your coding staff, and your clinical documentation team to make sure the routine cost rules are applied consistently across all service lines. |
| 6 | Loop in your compliance officer if your trial volume is significant. If your organization enrolls patients in multiple trials across multiple departments, the exposure here is real. A compliance officer or external billing consultant should review your current processes against the updated NCD 1 criteria before the effective date. Don't treat this as a low-priority refresh. |
| Previous Version | Current Version |
|---|---|
| Coverage is considered experimental and investigational for all indications | Coverage is considered medically necessary when specific criteria are met |
| Prior authorization is not required | Prior authorization is required for initial treatment |
| Documentation must include clinical history | Documentation must include clinical history |
| Re-review every 24 months | Re-review every 12 months with updated clinical documentation |
CPT, HCPCS, and ICD-10 Codes for Clinical Trial Routine Costs Under NCD 1
No Specific Codes Listed in This Policy
NCD 1 does not enumerate specific CPT, HCPCS, or ICD-10 codes. This is by design. The policy covers routine costs across all Medicare benefit categories — meaning the codes that apply to clinical trial billing are the same codes your team uses for those services in any other context.
The covered service determines the code. An outpatient E/M visit during a clinical trial bills the same E/M code it would outside the trial. A covered drug bills under the appropriate J-code. Durable medical equipment bills under the applicable HCPCS L- or E-code. Imaging bills under the applicable CPT radiology code.
What NCD 1 governs is whether those services qualify as routine costs — not which codes to use. Your standard billing guidelines for each service type still apply. Prior authorization requirements, fee schedule rates, and coverage criteria for each individual service remain in force regardless of the clinical trial context.
Affected Medicare Benefit Categories (Partial List)
The following benefit categories are explicitly referenced in NCD 1. Services within these categories may qualify as routine clinical trial costs when the three-part coverage test is met:
| Benefit Category | Notes |
|---|---|
| Inpatient Hospital Services | Standard inpatient billing rules apply |
| Outpatient Hospital Services | Including incident-to services |
| Ambulatory Surgical Center Facility Services | ASC facility billing rules apply |
| Physicians' Services | Standard professional billing applies |
| Drugs and Biologicals | Covered drugs; investigational drugs excluded |
| Durable Medical Equipment | Standard DME billing guidelines apply |
| Diagnostic Laboratory Tests | Only if clinically warranted, not protocol-only |
| Diagnostic X-Ray Tests | Only if clinically warranted |
| Home Health Services | Standard home health criteria apply |
| Skilled Nursing Facility | Standard SNF criteria apply |
| Hospice Care | Standard hospice rules apply |
| Nurse Practitioner Services | Incident-to rules apply |
| Physician Assistant Services | Standard PA billing applies |
| Oral Anticancer Drugs | Separately evaluated under coverage policy |
| Prosthetic Devices | Standard prosthetics billing applies |
| Orthotics and Prosthetics | Standard O&P billing applies |
This is not a complete list. NCD 1 explicitly covers all Medicare benefit categories that meet the three-part coverage test.
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