Written and maintained by CASRAI Editorial Board
Last updated
Not medical or legal advice. This guide describes how a federal enrollment system works; it is general information for lab, clinic and supply staff.
Short answer: what is PECOS?
PECOS is the Provider Enrollment, Chain, and Ownership System, a web-based platform run by the Centers for Medicare & Medicaid Services (CMS) for enrolling Medicare providers and suppliers. It is also where enrolled parties revalidate, update their information and track applications. A separate question, whether a clinician may order or certify items for Medicare patients, also depends on enrollment status, which is why PECOS comes up in supply, laboratory and imaging workflows.
Definition and scope
CMS describes PECOS as a platform that facilitates the enrollment process for Medicare providers and suppliers. The CMS PECOS fact sheet (December 2024) lists these uses: enrolling as a Medicare provider or supplier, revalidating, updating enrollment information in real time, and viewing and managing application statuses. It also covers reporting of ownership and managerial relationships, the “chain and ownership” part of the name.
The fact sheet says PECOS is available to individual providers such as physicians and nurse practitioners, medical groups and practices, hospitals, home health agencies and other facilities, and credentialing staff. Access runs through a user ID from CMS’s Identity & Access Management System (I&A).
How PECOS is used in practice
Enrolling to bill Medicare
A provider or supplier that bills Medicare enrolls, revalidates and updates its record in PECOS. For suppliers of durable medical equipment, prosthetics, orthotics and supplies (DMEPOS), the related steps are covered in our guides on Medicare revalidation for DME suppliers, the DMEPOS supplier standards and DMEPOS accreditation.
Being eligible to order or certify
The CMS “Ordering & Certifying” page (last modified 27 March 2026) sets out the conditions for ordering or certifying items and services for Medicare patients. The person must have an individual National Provider Identifier (NPI), be enrolled in Medicare in an “approved” or “opt-out” status, and be of an eligible specialty type. CMS states that organizational NPIs do not qualify and cannot be used to order or certify. A clinician who does not bill Medicare can still order and certify by opting out of Medicare or by enrolling as ordering/certifying only. The page applies this to orders for DMEPOS, clinical laboratory services, imaging services and home health services.
Two doors into the system compared
| Question | Enrolling to bill Medicare | Ordering or certifying | Source |
|---|---|---|---|
| What is the goal? | Enroll, revalidate and update a provider or supplier record | Be eligible to order or certify DMEPOS, laboratory, imaging and home health items for Medicare patients | CMS PECOS fact sheet; CMS Ordering & Certifying |
| Which NPI? | Fact sheet covers individuals, groups, hospitals and other facilities | Individual NPI only; organizational NPIs do not qualify | CMS Ordering & Certifying |
| Status needed | Enrollment in Medicare | “Approved” or “opt-out” | CMS Ordering & Certifying; 42 CFR 424.507(a) |
| Specialty | Not specified in the fact sheet | Must be an eligible specialty type | CMS Ordering & Certifying |
Where it matters for labs, clinics and supply decisions
Under 42 CFR 424.507(a), a claim for ordered imaging, clinical laboratory or DMEPOS items must contain the legal name and NPI of the physician or, when permitted, eligible professional who ordered the item. That orderer must be enrolled in Medicare in an approved status or have validly opted out. Home health and Part B drugs are excluded from this paragraph.
- Residents: the regulation says the claim identifies a teaching physician enrolled in approved status, or a licensed resident if state law permits and the resident is enrolled in approved status.
- Optometrists: CMS states they can only order DMEPOS supplies and laboratory or x-ray services payable under Medicare Part B.
- Eligible specialty list: CMS names physicians (MD/DO), dental medicine and surgery, podiatric medicine, optometry, physician assistants, clinical nurse specialists, nurse practitioners, clinical psychologists, interns, residents and fellows, certified nurse midwives, clinical social workers, marriage and family therapists and mental health counselors.
For supply staff, the practical point is that the orderer’s identity on an order is checked against Medicare enrollment, not only against a license.
PECOS, NPPES and PTAN
NPPES is the registry that holds NPI records; PECOS holds Medicare enrollment. The CMS fact sheet says the legal business name and the individual provider’s name must match between the two systems, and that updating a provider’s NPI record in NPPES does not automatically update Medicare enrollment in PECOS. A PTAN, the Medicare billing identifier, is a different number again; see our guide to the PTAN number and how it differs from an NPI.
Common misunderstandings
- “An organization’s NPI is enough to order.” CMS states organizational NPIs do not qualify for ordering or certifying.
- “Updating NPPES updates Medicare.” It does not, per the CMS fact sheet.
- “Only billing providers can order.” CMS says a clinician who chooses not to bill Medicare can still order and certify by opting out or enrolling as ordering/certifying only.
- “PECOS is only an application form.” The fact sheet lists revalidation, real-time updates, status tracking and ownership reporting as well.
FAQ
What is PECOS?
PECOS is the CMS web-based Provider Enrollment, Chain, and Ownership System used to enroll in Medicare, revalidate, update enrollment information and track applications (CMS PECOS fact sheet, December 2024).
What does PECOS stand for?
Provider Enrollment, Chain, and Ownership System.
How do users sign in?
Through a user ID issued by CMS’s Identity & Access Management System (I&A), according to the CMS fact sheet.
Who can order or certify items for Medicare patients?
CMS says the person needs an individual NPI, Medicare enrollment in an “approved” or “opt-out” status, and an eligible specialty type; organizational NPIs do not qualify (CMS Ordering & Certifying).
Sources
- CMS, Provider Enrollment, Chain, and Ownership System (PECOS) Fact Sheet, December 2024; checked 1 November 2026.
- CMS, Ordering & Certifying, last modified 27 March 2026; checked 1 November 2026.
- Legal Information Institute, 42 CFR 424.507; checked 1 November 2026.
