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CO-172 Denial Code: Payment Adjusted for Specialty

CO-172 means payment was adjusted, usually reduced, because the service was performed or billed by a provider of this specialty. Some payers pay different rates by specialty or provider type, and the payer applied that rule to this line.

Quick facts

Code
CO-172 (CARC 172)
Status
Active In use since June 30, 2005; last modified July 1, 2017.
Code set
Claim Adjustment Reason Codes (CARC)
Group codes
  • CO (Contractual Obligation): The reduction is a contractual adjustment the provider absorbs. It is not billable to the patient.
  • PR (Patient Responsibility): Rarely used. The patient may owe part of the amount if the plan pays less for that specialty and permits patient cost-sharing on the difference.
Official description
Payment is adjusted when performed/billed by a provider of this specialty. Usage: Refer to the 835 Healthcare Policy Identification Segment (loop 2110 Service Payment Information REF), if present.
X12 Claim Adjustment Reason Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What CO-172 means

CARC 172 reads “Payment is adjusted when performed/billed by a provider of this specialty.” Unlike CO-170, which denies payment, CO-172 reduces it. The payer’s fee schedule or contract pays this service at a different rate depending on who performs it.

The official usage note references the 835 Healthcare Policy Identification segment (loop 2110 REF), which may name the pricing policy.

Example: a plan pays some non-physician practitioners a percentage of the physician fee schedule. A service billed by one of those practitioners is allowed at the reduced rate, with the reduction reported as CO-172 in addition to any CO-45 amount.

Common causes

  • Specialty-based pricing in the payer’s fee schedule or your contract.
  • Taxonomy on the claim that differs from the rendering provider’s actual specialty.
  • Enrollment record errors at the payer listing the wrong specialty.
  • Billing a service under a mid-level provider when policy (and documentation) supported billing under the physician, or vice versa.
  • Group enrolled under one specialty while individual providers have others.
  • A provider’s board certification or specialty change not yet reported to the payer, so claims keep pricing under the old specialty.

How to fix it

  1. Check the rendering NPI in box 24J and the taxonomy reported on the claim.
  2. Compare to the payer’s enrollment record for that provider.
  3. Review the contract to see if the specialty-based rate is expected.
  4. If the specialty is wrong at the payer, update enrollment and ask for reprocessing of affected claims.
  5. If the claim reported the wrong rendering provider, submit a corrected claim with resubmission code 7.
  6. If everything matches the contract, post the reduction as a contractual adjustment.

How to prevent it

  • Keep taxonomy consistent across NPPES, payer enrollment, and your billing system.
  • Load specialty-specific fee schedules so expected payments are accurate.
  • Audit allowed amounts by rendering provider to catch specialty mismatches. ERA Analyzer compares payments across providers and payers to highlight unexpected reductions.
  • Follow supervision and billing rules carefully when choosing whose NPI to bill under. See NPI and enrollment denials.

Remark codes that may appear with CO-172

  • N95 (This provider type/provider specialty may not bill this service.): The specialty may not bill this service at all, a stronger statement than a reduction.
  • N381 (Alert: Consult our contractual agreement for restrictions/billing/payment information related to these charges.): Points to your contract, where specialty-based rates are usually defined.
  • CO-170 (Payment is denied when performed/billed by this type of provider.): Payment denied for the provider type, not just reduced.
  • CO-45 (Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement.): The standard fee schedule reduction that appears on most paid lines.
  • CO-171 (Payment is denied when performed/billed by this type of provider in this type of facility.): Denied for the combination of provider type and facility.

CO-172 FAQ

Why would a specialty change what I'm paid?

Some payer fee schedules pay certain provider types at a percentage of the physician rate, or pay specialists and primary care differently for the same service. The claim's taxonomy and enrollment determine which rate applies.

Is CO-172 a denial?

Not usually. It is a payment adjustment. It becomes a problem when the specialty on file with the payer is wrong, so the lower rate is applied by mistake.

How do I check if CO-172 was applied correctly?

Compare the allowed amount to your contract for the provider's actual specialty, and confirm the taxonomy on the claim matches the provider's enrollment with the payer.

Can I dispute a specialty-based rate?

If the rate matches your contract, the adjustment is expected and changes would come through contract negotiation. If the payer applied the wrong specialty, request reprocessing with proof of the provider's correct specialty.