Medicare participation and enrollment

Physicians, nonphysician practitioners, and other Medicare Part B providers must enroll in the Medicare program to be paid for the covered services and items they provide to Medicare beneficiaries. Providers must make their 2019 Medicare determinations by December 31. As the deadline approaches and providers consider their options with respect to Medicare participation, this column provides guidance to assist Fellows in navigating their contractual relationships with the Centers for Medicare & Medicaid Services (CMS).

What are the participation options?

Three participation options are available to surgeons. They are as follows:

  • Sign a participation (PAR) agreement. PAR providers choose to participate in the Medicare program and agree to furnish all covered services for all Medicare beneficiaries on an assigned claims basis.
  • Select nonparticipation (non-PAR) status. Non-PAR providers may choose on a case-by-case basis whether to accept Medicare assignment of claims. Providers who do not accept Medicare assignment may bill patients for more than the Medicare-allowed amount for a particular service.
  • Become a private contracting physician (opt out). Providers who opt out of Medicare participation must bill their patients directly and forgo any Medicare reimbursement.

How is payment determined for PAR providers?

PAR providers are contractually obligated to accept Medicare assignment for all claims involving a covered service that is furnished to a Medicare beneficiary. By agreeing to always accept assignment, providers also agree to always accept Medicare Physician Fee Schedule (MPFS)-allowed amounts as payment in full and not to collect more than the Medicare deductible and coinsurance or copayment from any beneficiary.

How are non-PAR providers paid?

When non-PAR providers accept assigned claims, they receive a total Medicare payment that is 5 percent lower than reimbursement to PAR providers. Non-PAR providers do not receive reimbursement directly from Medicare for the assigned claims they submit; instead, Medicare pays patients for 80 percent of a service’s MPFS-allowed amount. Patients are then responsible for passing on the Medicare payment plus the 20 percent copayment (which may be covered by supplementary insurance) to their providers.

For unassigned claims, non-PAR providers may bill up to 115 percent of the MPFS-allowed amount (that is, the “limiting charge”). The limiting charge is the maximum amount a non-PAR provider may legally charge a patient when filing an unassigned claim.

Can you provide more details about the difference between PAR and non-PAR reimbursement?

Payments made to PAR and non-PAR providers differ in three ways: the fee that is charged, the amount that Medicare and the patient pay, and where Medicare sends the payment. Table 1 shows how providers would be paid for a service with a $100 MPFS-allowed amount based on their Medicare payment arrangement.

Table 1. PAR and non-PAR reimbursement

Table 1. PAR and non-PAR reimbursement

What if I opt out?

Providers who opt out of Medicare cannot bill CMS or Medicare beneficiaries for services rendered. Providers who opt out may enter private contracting agreements with Medicare beneficiaries and charge patients without being subject to the MPFS. Such contracts, which must be signed by both the provider and patient, indicate that neither party will receive Medicare reimbursement for any covered services or items. Providers are prohibited from opting out on a claim-by-claim or patient-by-patient basis.

To opt out, providers must file an affidavit with CMS in which they agree to forgo Medicare reimbursement. CMS does not offer a standard opt-out affidavit form, but many Medicare Administrative Contractors (MACs) have forms available on their websites.1

PAR providers may opt out of Medicare at the beginning of each calendar quarter (January, April, July, or October). Non-PAR providers may opt out at any time.

How do I enroll?

Providers may make their Medicare participation decision for the upcoming calendar year during the designated annual open enrollment period, typically mid-November through December 31. PAR agreements for 2019 will cover the period from January 1 through December 31 and may not be changed once open enrollment has ended.

Providers should take the following steps to successfully enroll and participate in the Medicare program:

1. Obtain a national provider identifier (NPI)

You must be assigned a unique 10-digit NPI before enrolling in the Medicare program. To receive an NPI, submit an online, paper, or Electronic File Interchange (EFI) application.2 If you have already applied for an NPI, you can access the identifier via the National Plan and Provider Enumeration System NPI Registry.3

2. Complete the proper Medicare enrollment application

Once an NPI is assigned, you may enroll in the Medicare program, revalidate your enrollment, or change your enrollment information. Review CMS’ Medicare enrollment checklist to ensure you have all the required information before initiating the application process.4

You may submit either a paper enrollment application5 or complete an electronic enrollment application through the Medicare Provider Enrollment, Chain, and Ownership (PECOS) online portal.6

To avoid delays in application processing, verify the following before submission:

  • All required forms are appropriately signed and dated
  • All data elements are completed accurately
  • Supporting documents (such as tax forms, proof of licensure) are attached

If you are applying for Medicare enrollment, you must also pay an application fee electronically via PECOS. Applications will be rejected if the fee, which varies year to year, is not paid within 30 days of the application submission. The application fee for 2018 is $569.

3. Await application processing and respond to requests for more information

MACs process and screen all provider information on the enrollment application once it is submitted, and may employ additional review methods (for example, licensure verification, documentation requests, site visits) as needed. You should respond to any requests from your MAC as soon as possible, but within 30 days of the request. Failure to do so may delay enrollment or result in the rejection of the submitted application.

Once a MAC has determined a provider is eligible for Medicare billing privileges under CMS rules and regulations, the provider will receive an approval letter and will be designated as “approved” in PECOS.

4. Finalize enrollment

After receiving approval, a provider must submit the Medicare Participating Physician or Supplier Agreement (CMS-460) to the appropriate MAC to finalize enrollment.7 You have 90 days from when the CMS-460 is submitted to decide whether to accept your participation status or revoke your enrollment. If you choose to become a Medicare PAR, you must remain a participant until the following annual enrollment period conducted by your MAC.

5. Keep the information current

You should regularly verify the accuracy of your enrollment information on file with CMS and must formally revalidate your Medicare enrollment record information every five years. If you are actively enrolled in the program, visit the CMS website to find your revalidation due date. If you submit your application after the due date, your MAC may place a hold on your Medicare payments or revoke your billing privileges. In the event that your information changes following revalidation (for example, your practice moves to a different location), you should update your record in PECOS within 30 days of the event.

Where can I find more information?

For more information about the Medicare provider enrollment process, review the Medicare Learning Network Part B Enrollment Booklet or visit the ACS website. For more information, contact Lauren Foe, Regulatory Associate, ACS Division of Advocacy and Health Policy.


  1. Department of Health and Human Services. Centers for Medicare & Medicaid Services. Medicare fee-for-service provider enrollment contact list. Available at: Accessed October 30, 2018.
  2. Department of Health and Human Services. Centers for Medicare & Medicaid Services. National Provider Identifier (NPI) application/update form. Available at: Accessed October 30, 2018.
  3. National Plan & Provider Enumeration System. Electronic file management main page. Available at: Accessed October 30, 2018.
  4. Department of Health and Human Services. Centers for Medicare & Medicaid Services. Checklist for individual physician and non-physician practitioners using PECOS. Available at: Accessed October 30, 2018.
  5. Department of Health and Human Services. Centers for Medicare & Medicaid Services. Medicare enrollment application. Available at: Accessed October 30, 2018.
  6. Department of Health and Human Services. Centers for Medicare & Medicaid Services. Welcome to the Medicare Provider Enrollment, Chain, and Ownership System (PECOS). Available at: Accessed October 30, 2018.
  7. Department of Health and Human Services. Centers for Medicare & Medicaid Services. Medicare participating physician or supplier agreement. Available at: Accessed October 30, 2018.

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