Medicare credentialing is really Medicare enrollment. There is no credentialing committee and no negotiated fee schedule. You either meet the requirements or you do not, and the rate is published. That makes it more predictable than commercial credentialing. It is also less forgiving in one way: an enrollment problem stops payments outright rather than reducing them.
For the work itself, see our medical credentialing services.
How to get credentialed with Medicare, in short
- Get an NPI from NPPES, and an Identity and Access (I&A) account for PECOS.
- File the right CMS-855 application in PECOS: individual, group, or both.
- Reassign your benefits to the group if a group bills for you.
- Answer any development request from your Medicare Administrative Contractor (MAC) quickly; an unanswered one ends in rejection.
- Receive approval with your PTAN and effective date, then set up EFT and claims.
With us, approval usually comes in 15 to 30 days, depending on the MAC and whether the application comes back for more information.
Which form applies to you
| Form | Who files it |
|---|---|
| CMS-855I | Individual physicians and non-physician practitioners |
| CMS-855B | Group practices, clinics and most supplier organizations |
| CMS-855A | Institutional providers, hospitals, home health agencies, hospices |
| CMS-855S | DMEPOS suppliers |
| CMS-855R | Reassignment of benefits from an individual to a group |
| CMS-588 | Electronic funds transfer authorization |
The reassignment is the step people forget
A physician joining a group needs the individual enrollment and the CMS-855R reassigning their benefits to that group. Completing the 855I alone leaves the practice unable to bill for them. It is the most common Medicare enrollment error we are asked to unpick. It is usually found only when the claims deny.
PECOS
PECOS is the online system for all of this, and it is faster and easier to track than paper. You need an active NPI in NPPES first. You also need an Identity & Access account linked to it before PECOS will let you file. Access management is genuinely the fiddliest part of the process for most practices.
Effective dates and retrospective billing
Medicare is unusually generous here compared with commercial payers, and providers routinely leave the benefit unused.
- For physicians and most non-physician practitioners, the effective date is the later of two dates. Either the date the contractor received an application it went on to approve, or the date you first provided services at that location.
- There is normally a short retrospective billing window before that effective date. It lets you bill for care you have already given.
- This is why filing early matters even if you are not ready to see patients: the clock starts at receipt of the application, not at approval.
Revalidation: the one that stops payments
Set a calendar reminder the day you enroll
Medicare requires most providers to revalidate their enrollment every five years, and DMEPOS suppliers every three. The contractor sends a notice, but it goes to the address and contact on file, which is frequently an old practice manager's email.
Miss the deadline and your billing privileges are deactivated. Deactivation is not a denial you can appeal on clinical grounds; it is a switch that has been turned off, and reactivating it takes weeks during which nothing pays.
We track revalidation dates for every provider we enroll, because this is entirely preventable and expensive when it is not prevented.
Reporting changes
Certain changes must be reported within 30 days, including a change of ownership, a change of practice location and adverse legal actions. Most other changes are reportable within 90 days. Late reporting of an address change is one of the few administrative faults that can suspend an otherwise healthy enrollment.
Behavioral health: what changed in 2024
Mental health counselors (LPC, LMHC, LPCC) and marriage and family therapists became eligible to enroll in Medicare as independent providers on 1 January 2024. Before that, only psychologists and clinical social workers could bill Medicare directly.
Many therapists who wrote Medicare off years ago have not revisited that decision, and in most markets the panel is wide open as a result. See insurance credentialing for therapists and mental health providers for license-by-license detail.
Medicare Advantage is a different thing entirely
Being enrolled in traditional Medicare does not put you in network with any Medicare Advantage plan. MA plans are commercial contracts with their own credentialing, their own networks and their own fee schedules, and they must be applied for individually. Practices with large Medicare populations often discover this the hard way.
Before you touch a form: I&A and PECOS access
Almost every stalled PECOS enrollment we take over stalled in the same place, and it is not the application. It is access. PECOS does not hold its own logins. It reads them from a separate CMS system called Identity and Access Management, usually written I&A.
The order matters, and it only works one way:
- The provider creates their own I&A account. It is personal, tied to their own Social Security number, and nobody else can create it for them.
- The group creates or claims its own organization record in I&A, using the EIN.
- The provider or the group requests the connection between the two. The other side approves it.
- Only then can a staff member file or sign anything on the provider's behalf in PECOS.
Practices routinely lose two or three weeks here because the provider is busy and the approval email sits unread. If you are hiring, send the I&A step with the offer letter, not with the start date.
A surrogate is what CMS calls the staff member or billing company acting for a provider. Surrogacy is granted per provider and it does not transfer. If your biller leaves, their access leaves with them, and the new person starts the request over.
Participating, non-participating, or opted out
The Medicare enrollment process asks you to pick a status, and the form makes it look like a formality. It is not. It sets what you may charge for the rest of the year.
- ParticipatingYou accept assignment on every Medicare claim. Medicare pays you directly, you bill the patient only the coinsurance and deductible, and you are paid from the full fee schedule.
- Non-participatingYou decide claim by claim. Your fee schedule is 95% of the participating one. When you do not accept assignment you may charge the patient more, but only up to the limiting charge, and the patient pays you and waits for Medicare to reimburse them.
- Opted outYou are outside Medicare entirely and see beneficiaries under a private contract signed before care. Neither you nor the patient may bill Medicare for that care. Opt-out runs in two year periods and renews on its own unless you cancel it.
Two things practices get wrong. Opting out is not the same as simply not enrolling, and it is not a way to avoid paperwork. And a practice cannot be part in and part out: opt-out attaches to the individual practitioner across every place they work.
The participation choice can be changed, but only during the annual open enrollment window that CMS announces each autumn. Choose it deliberately at enrollment rather than discovering it in March.
When the application comes back
Three different things can happen to a CMS-855 enrollment, they are not the same, and the word on the letter tells you how much trouble you are in.
- ReturnedSomething was missing or unsigned, so the contractor never processed it. There is no appeal because there was no decision. You fix it and file again, and the clock restarts, which is the real cost.
- RejectedThe contractor asked for more information and did not get it inside the window they gave you. Same outcome as returned: refile from the beginning.
- DeniedAn actual decision was made against you. This one you can appeal, and you should, because a denial on the record follows the provider.
A denial is answered with a reconsideration request to the contractor, in writing, inside the deadline printed on the letter. Where the problem is something you can put right, such as a location that did not meet a site visit, the answer is usually a corrective action plan rather than an argument. Miss the deadline and the only route left is to enroll again from scratch.
The practical lesson is dull and it holds: most returns are caused by a blank field, an unsigned certification statement, or an address that does not match what the state license board holds. Read the application back against the license before it goes out.
Deactivation and revocation are not the same word
Both stop your claims, so practices treat them as one thing. They are very different problems.
Deactivation is administrative. It happens when you miss a revalidation, or when you do not bill Medicare for four consecutive quarters. Your enrollment record survives. You reactivate by filing a current application, and once it is processed your billing privileges come back. The damage is the gap: claims for dates of service inside it are generally not payable, and timely filing keeps running while you sort it out.
Revocation is a finding against you, for things like a felony conviction, a failed site visit, or billing for a provider who was not there. It carries a re-enrollment bar, which is a period during which Medicare will not take you back at all. The bar is set case by case and is measured in years, not weeks. It also has to be disclosed to commercial payers, which is how one Medicare problem turns into several.
If a letter uses the word revocation, treat it as urgent and get help the same week. The appeal windows are short and they are not extended for being busy.
Groups, locations and ownership
Enrollment follows the practice, not only the person. Three changes catch groups out.
A new location is its own enrollment record. Opening a second office and simply billing from it is one of the more common reasons a payment run stops. The location has to be on file before the claims arrive, and Medicare will check it.
Adding a provider to an existing group is the CMS-855R reassignment, and it needs the group's information as well as the provider's. Filing the individual enrollment and stopping there is the mistake we see most: the provider is enrolled, the group cannot bill for them, and nobody notices until the denials arrive.
A change of ownership is a formal process with its own timing, and it is not a matter of updating a name. If your practice is being bought or is buying, involve whoever handles enrollment before the closing date, not after it.
Institutional providers and certain supplier types also pay an application fee that CMS sets each year. Individual physicians and practitioners enrolling on the CMS-855I do not.
Medicare credentialing requirements
Medicare does not negotiate. If you meet the requirements, you are enrolled. For an individual practitioner they are:
- An active NPI with NPPES details that match the application.
- A current, unrestricted license in the state where you practice, for a provider type Medicare recognizes.
- No current exclusion from federal health programs and no unresolved Medicare debt or revocation bar.
- A practice location and correspondence details, and EFT bank details for payment.
- If a group bills for you, a reassignment of benefits to that group.
Groups and institutional providers add ownership and managing-control disclosures, and some provider types pay an application fee or face a site visit.
What "PECOS certified" means
People say a provider is PECOS certified when they mean the provider has an approved enrollment record in PECOS, Medicare's enrollment system. There is no separate certificate.
It matters most for ordering and referring. Claims for DME, lab, imaging and home health only pay if the ordering or referring practitioner has an approved Medicare enrollment record. A provider who never bills Medicare, but orders or refers for Medicare patients, can enroll for that purpose alone on the CMS-855O.
Medicare credentialing for physical therapists
Physical therapists in private practice enroll individually on the CMS-855I and, if they work for a group or clinic, reassign their benefits to it. Occupational therapists and speech-language pathologists in private practice follow the same pattern. Therapists who work only in a hospital or other institutional setting are generally billed under that institution's enrollment instead.
The plan of care and certification rules and the KX modifier threshold are billing issues rather than enrollment ones, but they decide whether the enrollment pays. See our physical therapy credentialing services.
Medicare enrollment FAQs
Which form do I need to enroll in Medicare?
Individual physicians and non-physician practitioners file the CMS-855I. Groups file the CMS-855B. A provider joining a group also needs the CMS-855R to reassign benefits to it, plus the CMS-588 for electronic payments.
Can I bill Medicare for patients I saw before approval?
Often, yes. The effective date is the later of the date the contractor received an approvable application and the date you first saw patients at that location, and there is normally a short retrospective billing window before it. That is why filing early matters.
How often does Medicare revalidation happen?
Most providers revalidate every five years, and DMEPOS suppliers every three. Missing it deactivates your billing privileges, and nothing pays until you are reactivated.
Can counselors and marriage and family therapists enroll in Medicare?
Yes, since 1 January 2024. Licensed mental health counselors and MFTs can now enroll as independent providers. See credentialing for therapists.
Does Medicare enrollment cover Medicare Advantage?
No. Medicare Advantage plans are private insurers that contract separately, although most of them require active Medicare enrollment first.
What does PECOS certified mean?
It means the provider has an approved Medicare enrollment record in PECOS. There is no separate certificate. Ordering and referring providers need that record for DME, lab, imaging and home health claims to pay.
Is PECOS enrollment required for Medicare Advantage plans?
Medicare Advantage plans credential providers through their own process, so PECOS enrollment alone does not put you in their networks. Many plans still ask for a Medicare enrollment, and ordering providers commonly need one, so most practices hold both.
What are the requirements for Medicare credentialing?
An active NPI, a current license for a provider type Medicare recognizes, no exclusion or revocation bar, a practice location, EFT details and, if a group bills for you, a reassignment. Groups also disclose ownership and managing control.
How long does Medicare enrollment take?
With us, usually 15 to 30 days, depending on the Medicare Administrative Contractor and whether it sends a development request. Answering requests quickly is the main thing you control.
Is there a fee to enroll in Medicare?
Not for individual physicians and practitioners on the CMS-855I. Institutional providers and certain supplier types pay an application fee that CMS sets each calendar year.
Can physical therapists enroll in Medicare in private practice?
Yes. Physical therapists in private practice enroll on the CMS-855I and reassign benefits to their group or clinic if it bills for them. Therapists working only in an institutional setting are billed under that institution.
What happens if Medicare revokes my enrollment?
Your billing privileges end and a re-enrollment bar applies, typically from one to ten years depending on the reason. Revocation is far more serious than deactivation, which can usually be reversed by revalidating.
Related
- The work itselfMedical credentialing and provider enrollment services
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