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N284 Remark Code: Referring Provider Taxonomy

N284 means the taxonomy code identifying the referring provider's specialty was missing, incomplete, or invalid. A payer that checks referral eligibility by specialty could not confirm what kind of clinician made the referral.

Quick facts

Code
N284 (RARC N284)
Status
Active In use since December 2, 2004.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): Provider-correctable. Supply or fix the taxonomy and resubmit; the patient is not billed.
Official description
Missing/incomplete/invalid referring provider taxonomy.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N284 means

Taxonomy codes describe a clinician’s type and specialty. Most payers identify the referring provider by name and NPI alone, but some also want the referring clinician’s taxonomy, usually because their rules depend on who is allowed to refer. N284 says that taxonomy was absent or not valid.

It is normally paired with CARC 16. If the payer found the taxonomy but concluded that the referring clinician isn’t permitted to refer for the service, you would more likely see CARC 183 or a remark such as N574.

Common causes

  • The payer’s requirement for referring taxonomy was never set up, so the value is never sent.
  • The referring clinician’s taxonomy was entered from memory and doesn’t exist in the code set.
  • The taxonomy reported differs from what NPPES lists for the referring NPI.
  • A general taxonomy was used where the payer expected the clinician’s specific specialty.

How to fix it

  1. Confirm with the payer’s billing instructions whether and how it accepts referring provider taxonomy.
  2. Look up the referring clinician in NPPES and note the primary taxonomy for that NPI.
  3. Add the taxonomy in the manner the payer specifies, alongside the referring name and NPI.
  4. Submit a corrected claim with frequency code 7 and the original claim number.

How to prevent it

For payers that require it, capture referring taxonomy when the referral arrives. Pulling it from NPPES by NPI avoids typos. Check authorization and referral denials for a front-end workflow that validates referring clinicians before the visit.

Codes that may appear with N284

  • CO-16 (Claim/service lacks information or has submission/billing error(s).): The claim is missing required information; N284 names the referring provider's taxonomy.
  • CO-183 (The referring provider is not eligible to refer the service billed.): Used when the referring provider is identified but not eligible to refer the service.
  • N286 (Missing/incomplete/invalid referring provider primary identifier.): The referring provider's NPI is the problem.
  • N285 (Missing/incomplete/invalid referring provider name.): The referring provider's name is the problem.
  • N574 (Our records indicate the ordering/referring provider is of a type/specialty that cannot order or refer.): The ordering or referring provider is of a type or specialty that cannot order or refer.
  • N288 (Missing/incomplete/invalid rendering provider taxonomy.): The rendering provider's taxonomy is the problem.

N284 FAQ

Where does referring provider taxonomy go?

There is no dedicated referring-taxonomy box on the paper CMS-1500, and support on electronic claims depends on the transaction version and payer. Follow the payer's companion guide for its instructions.

Why would a payer want the referring specialty?

Some plans only accept referrals from certain provider types, such as primary care, or need to verify that the referring clinician can refer for the service billed.

Which taxonomy should I report?

The primary taxonomy tied to the referring clinician's NPI in NPPES, unless the payer tells you to use the one on their enrollment record.