Guides · Billing guide

Dietitian insurance billing, step by step

By Javier Alvarez · Updated October 8, 2026 · 5 min read

This guide applies to private-practice RDs billing US commercial plans, Medicare and Medicare Advantage. Medicaid varies a lot by state; see Medicaid nutrition counseling for that side.

The whole workflow in one table

1. Get your NPI

Apply for a free National Provider Identifier through NPPES. Choose the taxonomy 133V00000X (Dietitian, Registered), or one of the more specific dietitian specializations in the NUCC list if it fits better. If you form a practice entity and bill under it, that entity needs its own Type 2 NPI, and the claim carries both: the group as billing provider and you as rendering provider. See NPI Type 1 vs Type 2.

2. Set up CAQH

Most commercial payers pull your credentials from CAQH (now the CAQH Provider Data Portal, formerly ProView) instead of a paper application. Fill in every section, upload your license, CDR registration and liability insurance certificate, authorize each payer to view the profile, and attest. Then re-attest every 120 days or payers stop seeing you as current. Our CAQH guide for dietitians walks through it.

3. Credential and contract with payers

Credentialing proves you are qualified; contracting sets your rates. You need both to be in network. Apply with each payer you want (start with the two or three biggest in your area), follow up every two weeks, and don't bill until you have a signed contract with an effective date.

For Medicare, enroll through PECOS as a registered dietitian or nutrition professional. Medicare Advantage plans credential separately, like commercial plans.

4. Check eligibility and benefits

Before the first visit, run an electronic eligibility check (an X12 270 request; the payer answers with a 271). It confirms the member is active and shows deductible, copay and coinsurance. The 271 often does not say whether MNT is covered or how many visits are allowed, so for new patients also confirm by phone or portal:

• Is MNT (97802/97803) covered, and for which diagnoses?
• Is there a visit or unit limit per year?
• Is a referral or prior authorization required?
• Is telehealth covered, and with which POS and modifier?

Record the call reference number. A wrong member ID or date of birth at this stage is what later becomes a CO-31 denial (patient cannot be identified as our insured). The benefits verification checklist has the full list of questions.

5. The visit and the note

Document face-to-face time, the assessment, the nutrition diagnosis, the intervention and the plan. Units come from time (see 97802 vs 97803), and the diagnosis that makes the visit covered must be documented by the referring or treating provider (see Z71.3 and Z68 codes).

6. Send the claim

The paper claim form for professional services is the CMS-1500; its electronic version is the 837P, which is what payers expect. A clearinghouse such as Claim.MD checks the claim for errors, routes it to the right payer ID, and reports rejections within hours. The fields that matter most:

• Patient name, date of birth and member ID exactly as on the card
• Diagnosis codes, with the covered condition first
• CPT code, modifier, POS, units and charge per line
• Rendering NPI, billing NPI, tax ID and taxonomy
• Referring provider name and NPI when the payer (or Medicare) requires a referral

7. Post the ERA (835)

The payer answers with an electronic remittance advice, the X12 835. For each line it shows the charge, allowed amount, payment and adjustments, each adjustment tagged with a group code (CO, PR, PI or OA) and a reason code (CARC). Post the payment, write off contractual adjustments (CO-45 is the usual one), and bill the patient for PR amounts such as PR-1 deductible, PR-2 coinsurance or PR-3 copay. Enroll for ERA and EFT with each payer so remittances and money arrive automatically.

8. Denials, corrections and appeals

Work denials weekly. Read the CARC and RARC, fix the root cause, and choose the right path:

See the denial code lookup for the codes RDs see most.

Timely filing

Every payer has a deadline to submit claims. Original Medicare allows 12 months (one calendar year) from the date of service. Commercial and Medicaid limits are set by contract or state rules and are often 90 to 180 days, sometimes shorter, and corrected claims and appeals have their own deadlines. A claim filed late is denied with CARC 29 and, in network, usually can't be billed to the patient. The fix is simple: submit within a few days of the visit. The timely filing calculator gives the last day for a date of service.

Worked example claim

A group practice billing a 45-minute follow-up for an in-network commercial patient.

837P, key fields

All data in this example is invented for illustration.