42 CFR 410.32: Diagnostic Test Orders, Supervision, and PECOS

42 CFR 410.32 is the Medicare Part B regulation that governs how diagnostic tests must be ordered and supervised. Every test billed under this rule must be ordered by the patient’s treating practitioner and performed under the supervision level CMS has assigned to that specific test code: general, direct, or personal. Billing a test that fails either requirement results in a claim denial.¹ As of January 1, 2026, CMS permanently allows direct supervision to be provided through real-time audio and video.²

Who Can Order a Diagnostic Test

The order must come from the physician who is actually treating the patient for the condition that prompted the test, and that physician must use the results to manage the patient’s care. A physician who signs orders without a genuine treating relationship does not satisfy the rule, and tests ordered that way are not considered reasonable and necessary.¹

Non-physician practitioners may also order tests when doing so falls within their state scope of practice and their Medicare benefit category. The regulation names nurse practitioners, physician assistants, clinical nurse specialists, nurse-midwives, clinical psychologists, clinical social workers, marriage and family therapists, and mental health counselors.¹ State law then dictates which specific tests each practitioner type can order.

Audiologists have a narrow exception. They may personally furnish diagnostic hearing tests once per patient every 12 months without a physician order, provided the test involves a non-acute hearing condition. The exception does not cover balance testing, hearing aids, or exams tied to prescribing or fitting hearing aids, and a CMS-designated modifier must appear on the claim.¹

The Three Supervision Levels

Every diagnostic test billed under the Medicare Physician Fee Schedule must be performed under at least general supervision. CMS assigns a specific level to each test code based on complexity and risk.¹

General Supervision

Under general supervision, the test is performed under the physician’s overall direction and control, but the physician does not need to be on-site. The physician remains responsible for training the non-physician staff and for the appropriateness and maintenance of the equipment.¹ Most routine lab work and basic imaging sits here.

Direct Supervision

Direct supervision requires the supervising practitioner to be present in the office suite and immediately available to assist throughout the procedure. Being in the same room is not required; being close enough to intervene without meaningful delay is.¹

Effective January 1, 2026, CMS has permanently adopted the rule allowing this immediate availability to be satisfied through real-time audio and video. Audio-only communication does not qualify. The virtual option does not apply to procedures carrying a 010 or 090 global surgery indicator.² Practices that built virtual supervision workflows during the pandemic-era waivers now have a permanent basis for that approach.

Personal Supervision

Personal supervision is the strictest tier. A physician must be physically in the room for the entire procedure. Virtual presence does not qualify, and only a physician, not an NPP, can provide it.¹ Few diagnostic tests carry this designation, but the ones that do tend to involve higher risk.

Finding the Level for a Specific Test

The regulation itself does not list levels test by test. CMS publishes a numeric supervision indicator for every CPT and HCPCS code in the Medicare Physician Fee Schedule Database (MPFSDB), and the database is the authoritative lookup.³ Assignments can change year to year, so a test that required general supervision last year may require direct supervision now. Confirming the current indicator before setting up a testing workflow is the practical compliance step that prevents avoidable denials.

Who Can Serve as the Supervisor

For general and direct supervision, the supervisor does not have to be a physician. The regulation allows the following non-physician practitioners to supervise when authorized under state scope of practice:¹

Nurse practitioners
Clinical nurse specialists
Physician assistants
Certified registered nurse anesthetists
Certified nurse-midwives

Personal supervision is different. The rule reserves it to a physician, so NPPs cannot supply it regardless of state authority. Nurse practitioners, clinical nurse specialists, physician assistants, and certified nurse-midwives may also perform diagnostic tests themselves, without a separate supervising practitioner, when state law permits.¹

Documentation and Signatures

A physician’s signature on the initial order is not required. What Medicare contractors look for on review is evidence in the medical record that the physician intended to order the test and that the test was medically necessary.⁴ A missing signature is not fatal on its own if intent and necessity are documented.

Phone orders work the same way. No signed order is needed at either end, but both the ordering office and the testing facility must document the call in the patient’s medical record, and the physician’s intent to order the test must be clearly recorded.⁵ If a signature is present but illegible, the provider can submit a signature log or attestation statement to verify who signed.⁴

The billing entity has its own documentation duty. It must keep the records it received from the ordering practitioner that substantiate the service, creating a two-sided paper trail: the ordering practitioner’s chart showing intent and necessity, and the biller’s supporting documentation showing the order existed.¹

PECOS Enrollment for the Ordering Practitioner

A valid clinical order is not the whole picture. The practitioner who orders the test must be enrolled in the Provider Enrollment, Chain, and Ownership System (PECOS) with either approved Medicare enrollment or a valid opt-out affidavit, and must have an individual National Provider Identifier. Organizational NPIs do not count for ordering.⁶

Practitioners who do not bill Medicare for their own services can still order tests, but only if they enroll solely as an ordering and certifying provider or opt out of Medicare. Without one of those enrollment paths, tests they order will not be covered.⁶ A state license alone does not make an order billable.

What Happens When the Rules Are Not Met

The immediate consequence is a denied claim. A diagnostic test performed without its required supervision level is not considered reasonable and necessary, and because that is a coverage determination rather than a billing error, the provider generally cannot bill the patient unless an Advance Beneficiary Notice was properly issued before the test.

When failures form a pattern rather than a one-off, exposure grows. Systematic billing for tests that lacked required supervision can trigger audits, overpayment recoupment, and potential False Claims Act liability. Enforcement actions in this area have produced multi-million-dollar settlements paired with years of independent claims monitoring. The patterns that draw attention are usually structural, such as naming a supervising physician who is not actually available or billing direct-supervision tests at locations where no qualified supervisor is present.

Where Different Rules Take Over

Two settings sit outside the office-based framework of 410.32 and are worth flagging so you do not apply the wrong rule. Independent Diagnostic Testing Facilities are governed by the companion regulation, 42 CFR 410.33, which adds site, staffing, and supervising-physician requirements on top of the ordering and supervision rules, and IDTFs face denial or revocation of Medicare billing privileges for noncompliance.⁷ Hospital outpatient departments follow the MPFSDB supervision levels for diagnostic services, but their direct supervision carries a geographic requirement (on-campus presence) that does not apply in the office setting, and all therapeutic services in that setting require direct supervision.⁸ Therapeutic services and durable medical equipment have their own ordering framework under separate provisions, though the treating-relationship and PECOS enrollment principles look similar.⁶

1
eCFR. 42 CFR 410.32 – Diagnostic X-Ray Tests, Diagnostic Laboratory Tests, and Other Diagnostic Tests: Conditions
2
Centers for Medicare & Medicaid Services. Calendar Year (CY) 2026 Medicare Physician Fee Schedule Final Rule
3
Centers for Medicare & Medicaid Services. Independent Diagnostic Testing Facilities – Physician Supervision
4
Centers for Medicare & Medicaid Services. Complying with Signature Requirements for Diagnostic Tests
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Centers for Medicare & Medicaid Services. Complying with Documentation Requirements for Lab Services
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Centers for Medicare & Medicaid Services. Ordering and Certifying
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eCFR. 42 CFR 410.33 – Independent Diagnostic Testing Facility
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Centers for Medicare & Medicaid Services. Common Questions About Supervision Requirements for Outpatient Services