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N288 Remark Code: Rendering Provider Taxonomy

N288 means the taxonomy code for the rendering provider, the clinician who performed the service, was missing, incomplete, or invalid. The payer uses it to match the service to the clinician's enrolled specialty.

Quick facts

Code
N288 (RARC N288)
Status
Active In use since December 2, 2004.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): A correctable claim error. Fix the rendering taxonomy and resubmit; the patient is not billed.
Official description
Missing/incomplete/invalid rendering provider taxonomy.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N288 means

The rendering provider is the individual who personally performed the service on a claim line. A taxonomy code tells the payer that clinician’s type and specialty, such as a physical therapist, a nurse practitioner, or a specific physician specialty. When a payer relies on taxonomy to apply fee schedules or verify enrollment and the value is blank or unrecognized, it returns N288.

Most payers attach it to CARC 16. Because it is a line-level element on professional claims, only some lines may be affected.

Common causes

  • The practice management system doesn’t send rendering taxonomy for this payer, even though the payer requires it.
  • Box 24I shaded area is missing the ZZ qualifier, so the payer can’t tell the value in 24J is a taxonomy.
  • The taxonomy is the group’s rather than the individual clinician’s.
  • The code reported doesn’t agree with NPPES or the payer’s enrollment for that NPI.
  • A clinician recently changed specialties or added a certification, and different systems now disagree.

How to fix it

  1. Identify the rendering clinician on each line with N288.
  2. Check the clinician’s primary taxonomy in NPPES and compare it with the payer’s enrollment record.
  3. Update the taxonomy in the clinician’s payer settings and make sure the ZZ qualifier is sent where applicable.
  4. Resubmit a corrected claim with frequency code 7 and the original claim number.

How to prevent it

Record each clinician’s taxonomy by payer when credentialing completes. When a clinician updates NPPES, review whether payer enrollments need matching updates. Claims for payers that require rendering taxonomy should be edited before submission for a blank or malformed value. More background on specialty and enrollment mismatches is in our provider enrollment denials guide.

Codes that may appear with N288

  • CO-16 (Claim/service lacks information or has submission/billing error(s).): Missing or invalid information; N288 identifies the rendering provider's taxonomy.
  • CO-185 (The rendering provider is not eligible to perform the service billed.): The rendering provider is not eligible to perform the service, which can follow when the taxonomy maps to the wrong specialty.
  • N290 (Missing/incomplete/invalid rendering provider primary identifier.): The rendering provider's NPI is the problem.
  • N255 (Missing/incomplete/invalid billing provider taxonomy.): The billing provider's taxonomy is the problem.
  • N94 (Claim/Service denied because a more specific taxonomy code is required for adjudication.): A more specific taxonomy is required.

N288 FAQ

Where does rendering taxonomy go on the CMS-1500?

In the shaded area of box 24J on the service line, with the ZZ qualifier in the shaded area of box 24I. Electronically, it is reported as the rendering provider's specialty information.

Do all payers require rendering taxonomy?

No. Many payers rely on the NPI alone, while some Medicaid programs and commercial plans require taxonomy to route claims correctly. Check each payer's instructions.

What if the clinician has more than one taxonomy?

Use the one that matches the specialty under which they are enrolled with that payer and that fits the service performed.