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A taxonomy code is a 10-character alphanumeric code identifying a healthcare provider’s type, classification, and area of specialization. It is selected at NPI registration, appears on claims, and must match what you enrolled with, or you get denials that look mysterious because nothing clinical is wrong. Maintained by the National Uniform Claim Committee (NUCC) and updated twice annually.1

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The structure

Ten characters, hierarchical: Example: 207N00000X, 20 allopathic and osteopathic physicians, 7N dermatology, no subspecialization.

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The failure mode

The taxonomy on your claim must match the taxonomy you enrolled with. A mismatch produces denials, commonly CARC 8 (procedure inconsistent with the provider type) or CARC 170, that look clinical but are purely administrative. Practices chase the coding when the problem is a data field set years earlier at NPI registration. Two distinct taxonomies exist and both must be right:
  • Group taxonomy on the PC’s Type 2 NPI, appearing in the 837’s PRV segment for the billing provider
  • Individual taxonomy on each clinician’s Type 1 NPI
Verify both against what each payer has on file at go-live, and again whenever you add a specialty or a location.

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Common codes by specialty

Illustrative working set. Confirm the current code for your specialty against the NUCC code set.

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Physicians (20 grouping)

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Groups

For a PC’s Type 2 NPI, use the specialty taxonomy if the practice is single-specialty, or 193200000X if genuinely multi-specialty. Do not use a clinic/center code unless you are licensed as one, some of those codes imply a facility license the practice doesn’t hold.

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Advanced practice and allied

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Behavioral health

🧠 A behavioral health group with several license types will have several individual taxonomies under one group taxonomy. Confirm each payer accepts the group taxonomy you chose for the mix of clinicians you employ. See Behavioral health.

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Dental

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Choosing at NPI registration

1

Individual (Type 1)

The clinician’s specialty. Where they are board-certified in a subspecialty, use the subspecialty code if payers in your market recognize it.
2

Group (Type 2)

The practice’s specialty, or the multi-specialty code if genuinely multi-specialty. Match it to what you will enroll and contract with.
3

Multiple taxonomies

NPPES permits more than one per NPI, with one designated primary. The primary is what most payers use. Adding secondary taxonomies is occasionally useful and occasionally creates confusion — do it deliberately.
4

Record both, everywhere

In your enrollment grid, alongside the NPI and Tax ID. This is the record you check when a CARC 8 arrives.

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When to change one

Update the taxonomy in NPPES when:
  • A clinician completes fellowship and changes specialty
  • The practice’s specialty mix changes materially
  • A payer tells you the enrolled taxonomy doesn’t match your services
Changing a taxonomy in NPPES does not update your payer enrollments. After changing it, notify each payer and confirm they updated their record. Otherwise NPPES and the payer disagree, and claims deny.

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Sources

  1. National Uniform Claim Committee, Health Care Provider Taxonomy Code Set. Updated twice annually. Verify current codes before registration.

Related topics

Get NPIs (Type 1 and Type 2)Enroll and contract with commercial payersSubmit clean claimsThe 837: how claims are told to payers837 file anatomyCARC codes (Claim Adjustment Reason Codes)