CO-B23: Procedure Not Authorized Per CLIA Proficiency Test
CO-B23 means the lab is not CLIA-authorized for this test. Appeal with your CLIA certificate if you are authorized, or refer to a certified lab.
What Does CO-B23 Mean?
When paired with Group Code CO, the CLIA authorization denial is contractual. The lab cannot bill for tests it is not certified to perform. The denied amount cannot be collected from the patient.
CARC B23 indicates the payer denied the claim because the laboratory performing the test is not authorized to do so under its Clinical Laboratory Improvement Amendments (CLIA) certification. CLIA requires all clinical laboratories to be certified and to meet quality standards for each type of testing they perform.
This denial occurs when the lab's CLIA certificate does not include the specific test category, the lab failed a proficiency test for the analyte, the CLIA certificate expired, the test falls outside the scope of the lab's certificate level (e.g., a waived lab performing moderate complexity testing), or CMS imposed sanctions restricting the lab's testing capabilities.
Laboratories must maintain proficiency testing compliance for every test they perform and bill. Failing a proficiency test for a specific analyte can result in loss of authorization to bill for that test until remediation is complete.
Common Causes
| Cause | Frequency |
|---|---|
| Lab not CLIA-certified for the test The laboratory's CLIA certificate does not authorize the specific test or category of testing billed on the claim | Most Common |
| CLIA proficiency test failure The laboratory failed a proficiency test for the specific analyte or testing category, resulting in loss of authorization to perform and bill for that test | Most Common |
| CLIA certificate expired or lapsed The laboratory's CLIA certificate expired and was not renewed before the date of service | Common |
| Testing outside CLIA certificate scope The laboratory performed testing that falls outside the scope of its CLIA certificate of waiver, registration, or accreditation | Common |
| CLIA sanctions imposed CMS or state authorities imposed sanctions on the laboratory restricting its testing capabilities | Occasional |
How to Resolve
- Review CLIA certificate Verify your certificate covers the test category.
- Check proficiency test status Confirm you passed the relevant proficiency test.
- Appeal with certificate If authorized, appeal with the CLIA certificate, number, and effective dates.
- Remediate if needed If proficiency testing failed, complete remediation and resubmit.
- Refer if not authorized If not authorized, refer future tests to a certified reference laboratory.
Appeal with a copy of the laboratory's current CLIA certificate showing authorization for the test category in question. Include the CLIA number, effective dates, and the list of authorized testing specialties/subspecialties. If a proficiency test was recently passed, include documentation of successful remediation.
Common RARC Pairings
The RARC code tells you exactly what triggered the CO-B23:
| RARC | Description |
|---|---|
| N130 | Alert: You may need to review plan documents or guidelines. Review your CLIA certificate to verify the authorized testing categories → |
| MA120 | Missing/incomplete/invalid information on the provider. Verify the CLIA number submitted on the claim and ensure it matches the testing authorization → |
How to Prevent CO-B23
- Maintain current CLIA certification and ensure timely renewal before expiration
- Successfully complete all required proficiency tests for each testing category
- Implement internal quality controls to pass proficiency tests consistently
- Bill only for tests within the scope of your CLIA certificate
- Track CLIA certification status and proficiency test results in your lab information system
- Refer tests outside your CLIA scope to certified reference laboratories
Also Filed As
The same CARC B23 may appear with different Group Codes:
Related Denial Codes
Sources
- https://x12.org/codes/claim-adjustment-reason-codes
- https://www.cms.gov/regulations-and-guidance/legislation/clia
- Codes maintained by X12. Visit x12.org for official definitions.