CO-171: Service not payable in this facility

The payer is telling you the CPT, HCPCS, or revenue code is nonpayable in the place-of-service or facility type you billed. They consider the service noncovered in that setting under their contract or benefit design, not just underpaid. Mechanically, the claim fails an edit that matches procedure or revenue codes to allowed facility types or POS codes. The payer sets the line to zero, applies CO-171 as a contractual denial, and you cannot bill the patient unless you overturn it with a corrected claim or appeal.

Behavioral health feels this often when hospital-based or free‑standing psych facilities bill office‑only codes or physician E&M codes on a UB-04. A PHP unit that bills 99213 with POS 22 instead of the correct PHP revenue code can hit a facility-type mismatch and get CO-171. Residential and detox programs see CO-171 when they bill H-codes or S-codes that the payer only allows in outpatient clinic or professional settings. For example, billing H0004 on a UB for a residential stay when the payer expects per-diem codes like H0018 or H2036 only. Telehealth adds another layer: some payers only allow 95 or 93 modifiers for professional claims, not for institutional facility claims. A PHP or IOP program that tries to bill telehealth group codes on a facility claim from a residential setting can get a facility-not-eligible edit that posts as CO-171.

• Confirm the billed place-of-service, type of bill, and facility type match the actual setting of care.
• Compare the denied CPT, HCPCS, and revenue codes against the payer's published facility-eligible code lists for that product line.
• If you used the wrong claim format or POS (for example UB instead of 1500, or 13 instead of 11), correct the claim and resubmit as a corrected claim.
• If the code is allowed but requires a different revenue code, modifier, or level-of-care code (PHP, IOP, RTC), rebill with the payer's preferred combination.
• If the payer policy truly excludes that service in your level of care, move the balance to contractual write-off and document the policy reference.
• If you believe the payer misclassified your facility type or applied the wrong policy, submit an appeal with license, contract excerpts, and comparable paid claims.

• Maintain payer-specific crosswalks that tie behavioral health CPT, HCPCS, and revenue codes to allowed facility types and POS codes.
• Configure your scrubber to flag any codes on UB-04 that the payer designates as professional-only, and any PHP/IOP per-diem codes billed on a 1500.
• Standardize templates by level of care so staff cannot pick office, inpatient, or residential POS incorrectly for PHP, IOP, or telehealth days.
• Review new payer contracts and bulletins for facility eligibility changes and update billing rules before you submit claims.