IDTF Billing Requirements & CMS-855B Enrollment Guide

Written by MedixCode Team

IDTF billing requirements are the Medicare rules an Independent Diagnostic Testing Facility must meet to get paid. You enroll each location on the CMS-855B with Attachment 2, meet the 17 performance standards, use qualified supervising physicians and technicians, bill only tests ordered in writing, and report changes on time.

Opening or expanding an IDTF is a major investment, and Medicare won’t pay your claims until your enrollment is approved. Screening includes a site visit, and CMS can inspect your facility unannounced.

This guide covers how CMS-855B enrollment works, the mistakes that delay approval and what it takes to keep your billing privileges. Where we cite rules, we link to the CMS source, including the CMS MLN booklet on IDTFs.

What Is an IDTF?

An IDTF is a diagnostic testing facility that is independent of both a physician’s office and a hospital. It can be a fixed location or a mobile unit, and Medicare pays for its tests under the Physician Fee Schedule.

Common IDTF services include:

Diagnostic imaging such as ultrasound, CT and MRI
Vascular studies
Sleep testing
Ambulatory cardiac monitoring
Nerve conduction studies
Pulmonary function testing

Not every testing entity should enroll as an IDTF. CMS says a facility that only performs diagnostic mammography should not enroll as one. Some tests personally performed by qualified audiologists, clinical psychologists and certain certified physical therapists are also exempt from the IDTF criteria.

Who Must Enroll on the CMS-855B?

IDTFs enroll in Medicare with the CMS-855B application (Clinics/Group Practices and Certain Other Suppliers), including Attachment 2 for IDTFs. Key enrollment rules from CMS:

The IDTF should be open and operational when it applies.
Each practice location enrolls separately. One CMS-855B can list only one IDTF practice location.
Each mobile unit enrolls separately, even if it belongs to a fixed site.
Adding a location requires a new complete application and its own site visit.

IDTFs also pay the Medicare enrollment application fee. For applications submitted in calendar year 2026, the fee is $750, according to the CMS notice in the Federal Register.

IDTF Billing Requirements: The 17 Performance Standards

When you complete Attachment 2, you certify that your IDTF meets the performance standards in 42 CFR 410.33(g). These are the ones that matter most day to day:

Standard	What CMS requires
Physical site	A real facility with space for the listed equipment, hand washing and patient privacy. A P.O. box, commercial mailbox, hotel or motel does not qualify.
Equipment	Testing equipment on site (portable units must be available for inspection within 2 business days), a current inventory with serial numbers, calibration to manufacturer standards and equipment changes reported within 90 days.
Liability insurance	At least $300,000 per location and per incident, carried by a non-relative-owned company. A lapse leads to revocation back to the date coverage ended.
Patient referrals	No direct solicitation of patients. Accept only patients referred by their treating physician or a qualified non-physician practitioner.
Reporting changes	Changes in ownership, location, general supervision and adverse legal actions within 30 days. All other changes within 90 days.
Records and access	Retrieve medical records within 2 business days, post your business hours and allow unannounced on-site inspections.
Shared space	Fixed-base IDTFs may not share a practice location, lease or sublease their operations, or share initial testing equipment with another Medicare-enrolled supplier.

Indirect IDTFs, which have no patient interaction at their location, are exempt from a few standards, including the insurance, complaint and posting requirements.

Supervising Physician, Interpreting Physician and Technician Rules

Supervising physician

Every IDTF needs one or more supervising physicians who oversee test quality, equipment operation and calibration, and the qualifications of non-physician staff. Each supervising physician must:

Hold a license in the state where the tests take place
Be enrolled in Medicare and not be excluded by the OIG
Be qualified for each test (code) listed on your application
Provide general supervision for no more than three IDTF sites

If a test requires direct or personal supervision under Medicare rules, the supervising physician must provide that level. Each supervising physician signs a separate attestation.

Interpreting physician

An IDTF is not required to have interpreting physicians. If you use them, they must meet the same license, enrollment and qualification rules, and you report them on the CMS-855B. A CMS-855I reassignment is not needed for an interpreting physician the IDTF employs or contracts with.

Technicians

Technicians must meet the license or certification rules of the state where they perform tests. If the state has no licensing board, they need certification from an appropriate national credentialing body. Keep this documentation ready for review.

Ordering Rules That Affect Every Claim

Every test must be ordered in writing by the treating physician or a qualified non-physician practitioner, and the order must state the diagnosis or reason for testing.
The IDTF’s supervising physician cannot order tests unless they are also the patient’s treating physician.
An IDTF cannot add tests based on internal protocols without a written order.
IDTFs cannot bill codes that are solely therapeutic.

A missing or incomplete order can cost you payment on a test that was otherwise performed and billed correctly.

The CMS-855B Enrollment Process, Step by Step

Confirm the enrollment type. Make sure IDTF enrollment fits your services and setting.
Gather your documents. Legal business name, TIN, organizational NPI, ownership and managing employee details, state licenses, liability insurance, equipment inventory, and credentials for supervising physicians, interpreting physicians and technicians.
Complete the CMS-855B and Attachment 2. List every CPT/HCPCS code you plan to bill, the equipment used for each and the personnel who perform, supervise and interpret the tests. You can apply online through PECOS or on paper.
Pay the application fee. CMS adjusts the fee every calendar year, so confirm the current amount before you apply.
Prepare for the site visit. IDTFs are a moderate-risk supplier type under 42 CFR 424.518, and moderate-risk screening includes an on-site visit. Your equipment, staff, signage and records should match your application from day one.
Receive approval. Your billing privileges start on the later of two dates: the date the MAC received an application it could process to approval, or the date you first furnished services at the location. Medicare does not pay for services before that date.

Processing time varies by MAC, application completeness and site visit scheduling, so plan your opening and cash flow with a buffer.

Opening a new IDTF or adding a location? Email us at info@medixcode.com with your enrollment questions.

Common CMS-855B Mistakes That Delay Approval

Leaving codes off Attachment 2. Standard 16 requires the IDTF to enroll for every diagnostic test it furnishes to Medicare patients.
Equipment that doesn’t match. The equipment on your application should be what the site visit finds.
Supervising physician gaps. Missing attestations, or physicians who are not qualified for the listed codes.
Insurance problems. Coverage below $300,000, or a policy issued by a relative-owned company.
Multiple locations on one application. Each location needs its own CMS-855B.
Applying too early. The facility should be open and operational when you apply.
Inconsistent details. Ownership or managing employee information that doesn’t match across documents.

Staying Compliant After Approval

Report changes within the 30-day and 90-day windows shown in the standards table above.
Report new test codes on an updated CMS-855B so your enrollment covers every test you bill.
Keep your liability insurance active at all times.
Revalidate when CMS asks. CMS states that most providers and suppliers revalidate every five years, and it can request off-cycle revalidation.

IDTF Billing Basics: Global, TC and Professional Component

Global billing: Allowed when the same entity performs both the technical component (TC) and the professional component (modifier 26) within the same Physician Fee Schedule payment locality.
Service location: For global claims, report the name, address and NPI of the location where the TC was performed in Items 32 and 32a, or the 837P equivalent.
Split billing: When the TC and modifier 26 are billed separately, report where each component was performed.
Anti-markup: If a physician working for the IDTF, or one related to it through common ownership or control, orders a test, the anti-markup payment limitation may apply.

How MedixCode Helps IDTFs

We support IDTFs with enrollment paperwork and day-to-day billing. Through our provider credentialing service, we help prepare CMS-855B applications and change reports. Our AAPC/CPC Certified Coders and Billers handle diagnostic medical coding, TC/26 splits and order checks.

We work inside your existing EHR/PM system, so your staff doesn’t learn new software. MedixCode is HIPAA compliant, and there is no setup fee, no monthly minimum and no long-term contract. See how our pricing works.

Explore our IDTF billing services. If your facility focuses on imaging or sleep and pulmonary testing, see our radiology billing for imaging centers and pulmonology billing pages.

FAQs

What is the CMS-855B form?

The CMS-855B is the Medicare enrollment application for clinics, group practices and certain other suppliers. IDTFs use it with Attachment 2, where they list their tests, equipment and personnel and certify they meet the 42 CFR 410.33(g) standards.

Is a site visit required for IDTF enrollment?

Yes. IDTFs fall in the moderate-risk screening category, so a site visit is part of screening. Adding a new practice location also triggers a separate site visit.

Does an IDTF need an interpreting physician?

No. Interpreting physicians are optional for an IDTF. Any you do use must be licensed, Medicare-enrolled, not excluded and qualified for the tests on your application.

How many IDTF sites can one supervising physician cover?

Up to three. That general supervision limit counts both fixed sites and mobile units.

Does an IDTF have to pay a Medicare enrollment fee?

Yes. IDTFs pay the institutional provider application fee when they first enroll, revalidate or add a practice location. The fee is $750 for applications submitted in 2026.

When can a new IDTF start billing Medicare?

Billing privileges begin on the later of the filing date of the approved application or the date the IDTF first furnished services at its location. Services before that date are not paid.

Final Thoughts

IDTF enrollment rewards preparation. A complete CMS-855B, qualified personnel, the right insurance and a facility that matches your paperwork help you avoid the most common delays. Accurate orders, coding and change reporting keep you enrolled.

Need help with IDTF enrollment or billing? Book a Free Consultation.

IDTF Billing Requirements: Complete CMS-855B Enrollment Guide