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N250 Remark Code: Assistant Surgeon Secondary ID Issue

N250 means a secondary identifier for the assistant surgeon, an ID used in addition to the NPI, such as a payer-assigned provider number or state license number, was missing, incomplete, or invalid.

Quick facts

Code
N250 (RARC N250)
Status
Active In use since December 2, 2004.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The assistant service was denied or held for a provider identifier issue. The provider corrects it; the patient is not liable.
Official description
Missing/incomplete/invalid assistant surgeon secondary identifier.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N250 means

Since the NPI became the standard, most payers rely on it alone. A few still ask for a second identifier, such as their own provider number or the clinician’s license number, to confirm enrollment or apply specific pricing. N250 says that extra identifier for the assistant surgeon was missing or unusable. It usually accompanies CARC 16.

The remark is narrow. It is not about the NPI (that’s N249), and not about the name or taxonomy (N248 and N247).

Why secondary IDs fail

  • The payer requires a secondary ID and none was sent.
  • The ID was sent with the wrong qualifier, so the payer read it as a different type of number.
  • A license number expired or was sent for the wrong state.
  • The payer-assigned number belongs to the surgeon or the group, not the assistant.
  • The billing system includes secondary IDs for surgeons but not for assistants.

How to fix it

  1. Check the payer’s companion guide to confirm which secondary identifier it wants for assistants and which qualifier applies.
  2. Look up the assistant’s correct number, such as the current license or the payer-assigned ID from enrollment.
  3. Add or correct the identifier and qualifier on the claim.
  4. Submit a corrected claim with resubmission code 7 and the original claim number.
  5. If the assistant isn’t enrolled and no payer ID exists, complete enrollment first.

How to prevent it

Include secondary identifiers in each clinician’s provider master record, by payer, with expiration dates for licenses. Check that assistants who join surgical cases are configured the same way as surgeons.

Codes that may appear with N250

  • CO-16 (Claim/service lacks information or has submission/billing error(s).): The claim has missing or invalid information; N250 names the assistant's secondary identifier.
  • CO-B7 (This provider was not certified/eligible to be paid for this procedure/service on this date of service.): The provider was not certified or eligible to be paid, sometimes because the secondary ID ties to enrollment.
  • N249 (Missing/incomplete/invalid assistant surgeon primary identifier.): The assistant surgeon's primary identifier, the NPI, was missing or invalid.
  • N247 (Missing/incomplete/invalid assistant surgeon taxonomy.): The assistant surgeon's taxonomy was missing or invalid.
  • N263 (Missing/incomplete/invalid operating provider secondary identifier.): The operating provider's secondary identifier was missing or invalid.

N250 FAQ

What counts as a secondary identifier?

Any identifier besides the NPI that a payer uses, such as a state license number, a payer-assigned provider ID, or, for some payers, a Medicaid provider number. Each is sent with a qualifier indicating its type.

Do most payers require secondary identifiers?

Many don't, now that the NPI is standard. Those that do, often certain Medicaid programs or specialty payers, describe it in their companion guides.

What if the qualifier is wrong?

The payer may read the number as the wrong type of ID and reject it. Make sure the qualifier matches the identifier you're sending.