Federal Requirements
Before you see your first patient, a set of federal registrations must be in place. These are not optional and they are not fast. Some take weeks. A few can take months. None of them can be processed retroactively — meaning if you miss one, you cannot bill for services rendered while the registration was pending. This section covers every federal requirement, what order to complete them in, and what happens if you get it wrong.
NPI Registration
The number that follows you for the rest of your career.
Your National Provider Identifier is a 10-digit number issued by NPPES — the National Plan and Provider Enumeration System. Every physician practicing in the United States is required to have one. You likely already do. If you trained and practiced elsewhere before opening your own practice, your NPI came with you.
What changes when you open an independent practice is that you now need a second NPI — a Type 2, issued to the practice entity itself — in addition to your individual Type 1. The Type 1 identifies you as a clinician. The Type 2 identifies your business. Both are required to bill insurance.
NPI types
| Type | Issued to | Required for |
|---|---|---|
| Type 1 | Individual physician | Billing as an individual provider |
| Type 2 | Practice entity (LLC, PC, PLLC) | Billing under a group or practice name |
What to do
Apply at nppes.cms.hhs.gov. Type 1 applications are typically approved within 10 business days. Type 2 applications require your business entity to be legally formed first — you cannot apply for a Type 2 until your LLC, PC, or PLLC exists and has an EIN.
What goes wrong
Submitting a Type 2 application before the business entity is legally formed causes delays. Entering taxonomy codes incorrectly causes payer enrollment issues later. Keep a copy of your NPI confirmation letters — payers will ask for them.
DEA Registration
Required in every state where you prescribe controlled substances.
If your practice involves prescribing controlled substances — Schedule II through V — you need a DEA registration. DEA registrations are state-specific. If you practice in multiple states, you need a separate registration for each state.
Registrations must be renewed every three years. Prescribing with an expired DEA registration is a federal violation under the Controlled Substances Act, regardless of whether it was accidental.
Application timeline: 4–6 weeks for a new registration. Renewals typically process faster, but do not wait until the expiration date — submit 60 days in advance.
What to do
Apply at deadiversion.usdoj.gov. You will need your state medical license (active, not pending), your NPI, your practice address, and your EIN. DEA registrations are tied to a specific practice location — if you move, you need to update the registration.
What goes wrong
Applying before your state license is active will result in rejection. Assuming one registration covers multiple states is a common and expensive mistake. Missing a renewal deadline means stopping all controlled substance prescribing until the renewal processes — there is no grace period.
Medicare & Medicaid Enrollment
The process that determines when you can bill government payers — and how far back you can go.
If your practice will accept Medicare or Medicaid patients, you must enroll before you can bill. Enrollment is separate from credentialing with commercial payers and has its own application process, timeline, and requirements.
Medicare enrollment is managed through PECOS — the Provider Enrollment, Chain, and Ownership System at pecos.cms.hhs.gov. Both your individual Type 1 NPI and your practice Type 2 NPI must be enrolled separately.
Medicaid enrollment is state-administered. Each state has its own portal, its own requirements, and its own timeline. If you practice in multiple states, you enroll separately in each.
Enrollment timeline: Medicare enrollment typically takes 60–90 days. Medicaid varies by state — some process in 30 days, others take longer. Both programs allow retrospective billing, but the lookback window is limited. Medicare’s standard retro-billing window is 30 days from your enrollment effective date. Do not assume you can bill indefinitely for services rendered before enrollment was approved.
Enrollment options
| Option | Description |
|---|---|
| Participating provider | Accepts Medicare assignment — billed amount is limited to the Medicare-approved rate |
| Non-participating provider | Can bill up to 15% above Medicare rates — patients pay the difference |
| Opt-out | Does not bill Medicare at all — requires a signed private contract with each Medicare patient |
Most independent physicians enroll as participating providers. Opting out is a legitimate choice for direct-pay practices, but the decision is binding for two years.
What goes wrong
Starting to see Medicare or Medicaid patients before enrollment is approved means those claims cannot be billed. The 30-day retro window is shorter than most physicians expect. Missing the application deadline relative to your open date can create a gap in billable revenue that cannot be recovered.
Tax Registrations
The registrations that make your practice a legal employer and taxpayer.
Employer Identification Number (EIN)
Your EIN is issued by the IRS and identifies your business entity for tax purposes. Apply at irs.gov — approval is immediate when done online. Your EIN is required before you can open a business bank account, apply for an NPI Type 2, apply for a DEA registration, hire employees, or enroll in Medicare.
This should be the first thing you do after your business entity is formed.
State tax registration
Most states require a separate tax registration for businesses operating within their borders. Requirements vary — some states issue a general business tax ID, others require separate registrations for payroll tax, sales tax (if applicable), and employer withholding. Check your state’s department of revenue for the specific requirements.
What goes wrong
Skipping state tax registration is common and creates problems when you later try to open payroll, hire staff, or respond to state tax authority correspondence. Do this at the same time as your EIN — it takes 30 minutes and avoids downstream headaches.
CLIA Waiver
Required if you run any in-office lab tests.
The Clinical Laboratory Improvement Amendments — CLIA — regulate laboratory testing performed on humans in the United States. If your practice performs any in-office diagnostic testing, you need a CLIA certificate.
Waived tests are low-complexity tests approved for office use: urine dipstick, blood glucose, urine pregnancy, rapid strep, rapid flu, rapid COVID, hemoglobin, and others on the CMS waived test list. A CLIA Certificate of Waiver covers all tests on the waived list and is sufficient for most primary care and general specialty practices.
Higher complexity testing — cultures, most hematology panels, coagulation studies — requires a higher CLIA certificate category with additional requirements and inspections.
What to do
Apply through your state agency or directly through CMS at cms.gov/CLIA. The Certificate of Waiver application costs $180 and is valid for two years. Apply before you plan to offer any in-office testing — running tests without a CLIA certificate is a federal violation.
What goes wrong
Assuming you do not need CLIA because you are “just doing a few simple tests” is the most common mistake. If the test is on the waived list and you are running it in your office on patients, CLIA applies. There is no minimum volume threshold.
Completion order
The sequence matters. Some of these registrations depend on others being in place first.
| Step | Registration | Depends on |
|---|---|---|
| 1 | Form business entity | Nothing |
| 2 | Apply for EIN | Business entity formed |
| 3 | Apply for NPI Type 2 | EIN issued |
| 4 | Apply for DEA registration | State license active |
| 5 | Enroll in Medicare / Medicaid | NPI Type 1 and Type 2 active |
| 6 | Complete state tax registrations | EIN issued |
| 7 | Apply for CLIA waiver | Practice address confirmed |
Your NPI Type 1 should already exist. If it does not, apply for it first — before anything else on this list.
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