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Notes on payer behavior

CO-170 and CO-171 denial codes: not payable for this type of provider

Clearia · September 2026 · denial codes, read properly

Denial codes CO-170 and CO-171 are the payer saying: "CO-170: Payment is denied when performed/billed by this type of provider. CO-171: Payment is denied when performed/billed by this type of provider in this type of facility." What that means for your practice, and whether it's worth chasing, below.

What the payer is asserting

The service is fine and the patient is covered. The problem is who billed it. CO-170 says this provider type can't be paid for this service under the plan. CO-171 adds a setting: this provider type can't be paid for this service in this kind of facility. In an independent surgical practice the provider type in question is nearly always a physician assistant or nurse practitioner, and occasionally a therapist, an athletic trainer, or a physician whose enrollment with the payer doesn't cover the specialty billed.

What it usually is

Is it recoverable?

Usually, and it is documentary. Enrollment gap: reprocess from the effective date. Wrong billing convention: corrected claim under the right NPI or with the right modifier. Wrong place of service: corrected claim. The trap is timing. A credentialing application that takes ninety days while the extender sees patients builds ninety days of CO-170s, and some of them will cross the payer's corrected-claim window before the enrollment comes through. Hold the claims rather than sending them to be denied, and diary the effective date.

Workers' comp

Florida workers' comp has its own version, EOBR code 26, "service rendered by healthcare practitioner outside scope of practitioner's licensure," and pays non-physician surgical assistants at "seventy-five percent (75%) of twenty-five percent (25%) of the physician MRA" with modifier AS, where the carrier has determined the assistant meets state licensure. The manual's rules.

Questions people ask about CO-170 and CO-171

What does denial code CO-170 mean?

The payer won't pay for this service when it is performed or billed by this type of provider. In practice it usually means a physician assistant or nurse practitioner who isn't enrolled with the payer, or a service billed under the wrong provider convention for that plan.

What is the difference between CO-170 and CO-171?

CO-171 adds the setting: the provider type isn't payable for this service in this type of facility. A wrong place-of-service code is a common cause, so check that before assuming a credentialing problem.

How do you fix a CO-170 denial?

Confirm the provider's enrollment effective date with the payer and reprocess claims from that date. If the payer expects the service billed under the supervising physician or with a specific modifier, submit a corrected claim that way. Hold claims for a provider whose enrollment is pending rather than sending them to be denied.

Want every line with this code from the last year sorted into fixable and not? Clearia's free diagnostic reads a year of your remittances, groups the denials by insurer and reason, and reports the recoverable ones in dollars with their deadlines. We're paid only from what we recover.

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