Medicare enrollment and credentialing for a new PT practice

Two approvals stand between a new physical therapy practice and its first paid claim, and they have almost nothing in common. Medicare enrollment is regulation: the forms are numbered, the effective date is defined in the Code of Federal Regulations, and the back-billing window is written down to the day. Commercial credentialing is a negotiation wearing a process costume. Vendor blogs blur the two into one chore called “getting credentialed,” and owners who inherit that blur apply the wrong expectations to both halves.

How does a physical therapist enroll in Medicare?

The sequence comes straight from CMS’s Medicare Provider Enrollment booklet: first an NPI through NPPES, then the enrollment application itself, online through PECOS or on paper.

The paper forms tell you what you are, so they are worth knowing even if you file online. A physical therapist in private practice, including a PT who is the sole owner of a corporation or LLC, enrolls with the CMS-855I; the form’s own eligibility list names “occupational or physical therapists in private practice.” A practice enrolling as a group files the CMS-855B, whose list names “physical or occupational therapy groups in private practice.” Each treating therapist still enrolls individually, then reassigns their benefits to the group so the practice, not the individual, gets paid. The separate reassignment form is gone: CMS has merged the CMS-855R into the CMS-855I. And none of this costs money. The $750 application fee for 2026 falls on institutional providers and suppliers like DMEPOS companies, not on therapists or their groups.

Two rules shape a PT enrollment specifically. Chapter 15 of the Medicare Benefit Policy Manual requires each therapist billing Medicare directly to be enrolled as a private practitioner, and it confines where the services can happen: the therapist’s or group’s office, or the patient’s home. The office has to be space the practice owns, leases, or rents and uses exclusively for the practice. A sublet treatment room inside someone else’s gym deserves a careful read of that section before it goes on the application.

Enrollment is also not a one-time event. Providers generally revalidate every five years, and your Medicare Administrative Contractor (MAC) sends the notice 90 to 120 days before the due date; missing it can hold payments or deactivate billing privileges.

How far back can a newly enrolled PT bill Medicare?

This is the money question, and it has an exact answer. Under 42 CFR 424.520(d), the effective date of billing privileges is the later of two dates: the day you filed an enrollment application that was subsequently approved, or the day you first began furnishing services at the new practice location. Physical therapists are named in the regulation’s list. Notice which date is missing from that formula: the approval date. File in March, open in April, get approved in June, and your effective date is April.

Then 42 CFR 424.521 adds a grace window behind that date. A physical therapist, again named in the list, may retrospectively bill for services furnished up to 30 days before the effective date, if circumstances precluded enrolling in advance, all program requirements including state licensure were met, and the services happened at the enrolled practice location. The window stretches to 90 days only when a Presidentially declared disaster is what stopped you from enrolling.

Thirty days sounds generous until you put a real ramp-up against it. A new clinic that starts treating in week one and files its application in week eight has donated a month of visits, and no appeal recovers them, because nothing was denied. The rule was followed. Treat the retrospective window as a safety net for the application that hits a snag, not as schedule slack, and file with the MAC before the first Medicare patient is ever booked.

Participating, non-participating, and the math between them

Once enrolled, you get a choice with a deadline: 90 days from your initial approval letter to decide whether to be a participating provider, by filing the CMS-460 agreement. Miss the window and the decision waits for the annual open enrollment period, generally mid-November through December 31.

Participation means accepting assignment on every covered service. The allowed amount is the whole fee, you collect nothing from the patient beyond the deductible and coinsurance, Medicare pays you directly, and claim information crosses to Medigap insurers on its own. Decline to participate and the arithmetic changes twice. First, under the Medicare Claims Processing Manual’s differential rule, payment to any nonparticipant may not exceed 95 percent of the fee schedule amount, and the manual applies that five percent reduction to independently practicing physical therapists by name. Second, the limiting charge rules cap what you can charge the patient at 115 percent of that already-reduced non-par amount, and outpatient PT services from an independently practicing physical therapist sit explicitly on the list of services the cap covers. Run the two together and the ceiling works out to 109.25 percent of the participating rate, collected from the patient rather than the program. A non-par PT can still accept assignment claim by claim; what nobody escapes is claim submission itself, which CMS notes the Social Security Act requires whether you participate or not.

Whether the extra 9.25 points are worth the collections risk depends on numbers that move every year; what the fee schedule actually pays a PT practice is its own conversation.

Can a physical therapist opt out of Medicare?

No. This is the fact that surprises new owners most, usually ones arriving with a cash-based plan, and it is stated flatly in section 40.4 of the Benefit Policy Manual: “Physical therapists in independent practice and occupational therapists in independent practice cannot opt out because they are not within the opt out law’s definition of either a ‘physician’ or ‘practitioner’.”

Opt-out, the mechanism that lets a clinician leave Medicare and privately contract with beneficiaries at unrestricted rates, is open to a closed list: physicians as the statute defines them, and a practitioner roster that runs from physician assistants and nurse practitioners through clinical psychologists and registered dietitians. Therapists are not on it, and neither are chiropractors. For a PT, there is no private-contract lane around the program: for covered services to a Medicare beneficiary, the mandatory claim submission rules and the charge limits above are the operating reality. The manual’s one exception is narrow, a beneficiary who refuses, of their own free will, to authorize a claim, and even then the limits on what you may collect still apply. Build the cash-pay wing of a practice with that sentence in front of you.

Credentialing and contracting are two different yeses

Everything above came from a regulator. Cross into commercial payers and the sourcing changes, because the process belongs to each payer.

The vocabulary still has edges worth keeping. Credentialing is verification. Washington state’s credentialing statute defines it as “the collection, verification, and assessment of whether a health care provider meets relevant licensing, education, and training requirements.” Contracting is the separate agreement that puts you in network and sets your rates. The distinction matters because a credentialed therapist without a countersigned contract is still out of network. Washington’s statute says so in its own dry way: the credentialing section “does not require health carriers to approve a credentialing application or to place providers into a network.”

The one piece of shared infrastructure is the provider profile formerly known as CAQH. Payers that use it pull their verification data from a single repository instead of asking you to re-document your license and training on every application, so the practical first step of commercial credentialing is completing that profile and keeping it attested. The organization behind it rebranded as DataSpring in June 2026 and says it maintains more than 4.8 million provider-sourced records; your credentialing paperwork will use both names for a while yet.

On timelines, honesty beats precision. You will read that credentialing takes 90 to 120 days. Ask where that number comes from; the pages repeating it never cite a publisher. What exists instead is a patchwork of state prompt-credentialing laws. Washington’s RCW 48.43.750 requires a carrier to approve or deny a complete application within 90 days, with all determinations averaging no more than 60 days. That is Washington’s rule, binding on Washington carriers, and if your state has an equivalent it is worth finding, because it converts an open-ended wait into a deadline you can cite in a follow-up call.

What a new practice can run in parallel

Sequence this like a project, because it is one. NPIs come first, since nothing files without them. The legal entity, EIN, bank account, and malpractice policy come next, because the enrollment and credentialing applications all ask for them. Then the Medicare application goes to the MAC before the first Medicare patient is booked, with the 30-day window held in reserve. The DataSpring profile can be built the same week, since commercial credentialing runs on its own clock and shares no dependency with PECOS. Contracting talks start when credentialing clears.

The same logic applies to every therapist you hire afterward, which is where the software question quietly sits. A second hire whose payer approvals are still pending is a scheduling problem and a verification problem at once. Eligibility checks at booking are included in both Orion plans, so the front desk knows what a payer will say before the visit exists. On Pro Plus, claim submission runs inside the same system, with a dedicated billing-operations contact instead of a ticket queue. Orion does not do your credentialing, and no EHR honestly can. What the pricing model does do is stay out of the way while you staff up. Only billing providers pay, so the therapist who cannot yet bill is not a license fee while you wait on the payers.

The Medicare half of this you can read tonight, section numbers and all, and it will behave exactly as written. The commercial half will behave like the payer it belongs to. Budget your patience accordingly, and your filing dates precisely.