CO-151: Payment adjusted because the payer deems the information submitted does not support this many/frequency of services.
The payer is saying the number of units, visits, or frequency billed is not supported by the documentation, or exceeds what is typically expected for this diagnosis and procedure combination. This is a frequency or utilization denial, not a hard benefit exclusion.
What the group code means
- CO
- Contractual Obligation. The provider is responsible and the amount cannot be billed to the patient.
This CARC is reported under more than one group code depending on the payer and the circumstances: PR, CO.
Why it fires
- Units billed exceed the payer's frequency edit or medically unlikely edit for the code
- Documentation does not support why this many visits or units were medically necessary
- The same service was billed multiple times in a period the payer considers excessive absent justification
Corrective actions, ranked
- 1
Review MUE and frequency edits
Check CMS medically unlikely edit tables or the payer's frequency policy for the code to see the allowed units or visits.
- 2
Submit supporting documentation
If the higher frequency is clinically justified, send progress notes and the treatment plan explaining medical necessity for the volume billed.
- 3
Correct billing errors
If units were entered incorrectly, such as billing per unit instead of per session, correct and resubmit.
Is it worth appealing
Appeal with documentation demonstrating clinical necessity for the frequency billed. Routine or vague notes rarely overturn this denial.
Retrieved 2026-07-18.
Do not let this happen again
Scrub the claim against NCCI PTP and MUE edits before you submit, free and in your browser.
DenialPath provides billing and administrative guidance based on published CMS and X12 sources. It is not medical advice, not a coverage determination, and not a guarantee of payment. NCCI and MUE edits are republished quarterly and payer policies vary by contract. Always confirm against the payer's own current policy before submitting or appealing.