CO-173: Service Not Prescribed by a Physician
Provider responsibility — correct and resubmit to the appropriate payer. The patient is not liable for this amount.
What Does CO-173 Mean?
With CO (Contractual Obligation), the CARC 173 adjustment for service not prescribed by a physician indicates the claim needs to be corrected or routed to a different payer. The patient is not liable for this amount. Correct the issue and resubmit.
CARC 173 is used when the payer determines that service not prescribed by a physician. The claim could not be processed as submitted because required information was absent, incomplete, or did not meet the payer's submission standards.
Common scenarios that trigger this adjustment include: the service or equipment requires a physician's order or prescription to be covered, but no order was on file or referenced on the claim at the time of submission; The order was written by a non-physician practitioner (NP, PA) but the payer requires a physician's order for this specific service or equipment; The physician's prescription or order has expired and is no longer valid for the date of service. The group code paired with CARC 173 determines who bears the financial responsibility — CO places it on the provider as a contractual obligation, PR shifts it to the patient, OA indicates a coordination of benefits or other payer adjustment.
Common Causes
| Cause | Frequency |
|---|---|
| Missing physician order or prescription The service or equipment requires a physician's order or prescription to be covered, but no order was on file or referenced on the claim at the time of submission | Most Common |
| Order from non-physician provider not accepted The order was written by a non-physician practitioner (NP, PA) but the payer requires a physician's order for this specific service or equipment | Most Common |
| Expired or outdated prescription The physician's prescription or order has expired and is no longer valid for the date of service | Common |
| Prescription not on file with the payer The prescription was obtained but not submitted to or recorded by the payer, so the payer has no record of a physician's order | Common |
| Self-referred service requiring physician order The patient self-referred for a service that requires a physician's order under the payer's policy, such as DME, home health, or certain therapies | Common |
How to Resolve
- Review the denial reason Examine the CO-173 adjustment and any RARC codes to identify what needs to be corrected.
- Correct the claim Address the issue that triggered the denial — update the claim with correct information or route to the appropriate payer.
- Resubmit the claim Submit the corrected claim per the payer's guidelines.
This denial indicates no physician prescription was on file. Obtain the physician's order and resubmit the claim with the prescription documentation rather than filing an appeal.
Common RARC Pairings
The RARC code tells you exactly what triggered the CO-173:
| RARC | Description |
|---|---|
| N130 | You may need to review plan documents or guidelines Review the payer's physician order requirements for this service or equipment → |
| M127 | Missing/incomplete/invalid documentation/orders/notes Submit the physician's order or prescription to support the claim → |
How to Prevent CO-173
- Verify that a valid physician's order or prescription is on file before providing services that require one
- Know which services require a physician's order versus those that can be ordered by non-physician practitioners for each payer
- Track prescription expiration dates and obtain renewals before they expire
- Submit physician orders with the initial claim when the payer requires them
- Implement intake procedures that verify prescription requirements before scheduling services
Also Filed As
The same CARC 173 may appear with different Group Codes:
Related Denial Codes
Sources
- https://www.mdclarity.com/denial-code-carcs
- https://x12.org/codes/claim-adjustment-reason-codes
- https://portal.ct.gov/-/media/ohs/health-it-advisory-council/apcd-advisory-group/data-submission-guide-workgroup/meeting-materials/6-30-22/carc-codes_final.pdf
- https://medicaid-documents.dhhs.utah.gov/Documents/pdfs/ClaimDenialCodes.pdf
- Codes maintained by X12. Visit x12.org for official definitions.