CO 152 denial code

Claim adjustment reason code 152. Often reported as CO 152.

Records do not support length of service

Unofficial reference. This is our own plain-English explanation, not the official code text. Payer rules differ. Verify with the payer and the official X12 code list. AlphaPrefix is not affiliated with X12, CMS or any payer. Data last updated Nov 11, 2026.

What 152 means

The payer decided the documentation does not justify how long the service, stay or treatment lasted.

This code is about duration. It often shows up on inpatient days, therapy time or other services measured in time, where the payer agrees with part of the length billed but not all of it.

The remittance may carry a policy reference that explains the payer's criteria. Look for it, because it tells you which rule the payer applied.

Group codes seen with 152

On a remittance, 152 comes after a group code. These are the ones it is most often reported with:

• CO 152 (Contractual Obligation): The provider's side of the ledger. The reduction comes from the payer contract or a rule the provider has to follow, and the patient normally cannot be billed for it.

The payer chooses the group code for each adjustment, so the same reason code can appear with another group code on your remittance. Read the two together. More about group codes.

Common causes

• Extra inpatient days were not supported by the clinical record.
• Timed services lasted longer than the documentation supports.
• The record did not show why treatment needed to continue for the period billed.

What to do next

1. Check the remittance for any policy reference that explains the decision.
2. Review the record for documentation that supports each day or time unit billed.
3. Appeal with the records that justify the length when the service was medically needed.

Related codes

• 150 (reason code) Records do not support level of service
• 151 (reason code) Records do not support number or frequency
• 50 (reason code) Not medically necessary per the payer