CO-152 Denial Code: Length of Service Not Supported

What CO-152 means

CARC 152 says the payer “deems the information submitted does not support this length of service.” In other words, the payer looked at what you billed and at the documentation it had (or did not have) and concluded the service lasted, or needed to last, less than the claim says.

“Length” is broad. It covers timed sessions (such as a psychotherapy session billed at a longer time tier), inpatient or residential days, skilled nursing or home health episodes, and rental periods. The official usage note points to the 835 Healthcare Policy Identification segment (loop 2110 REF). If present, that reference names the payer policy that set the limit, which is the first thing to read.

Example: a practice bills an extended session, but the note only records a start time with no end time. The payer cannot confirm the duration and returns CO-152, either denying the line or paying at a shorter time tier.

Common causes

• Missing start and stop times in notes for services billed by time.
• Time documented falls below the threshold for the code or units billed in box 24D and 24G.
• Inpatient or residential days exceed what the payer’s utilization review approved.
• Authorization covered fewer days or sessions than were delivered, and the extra length was not re-reviewed.
• Payer policy caps duration (for example a maximum session length or episode length) that the claim exceeded without supporting notes.
• Records not sent when the payer requested them, so the payer decided on the claim data alone.

How to fix it

1. Read the ERA and the policy reference. Check whether the line was reduced or denied, and look for a REF policy identifier or remark code that explains the limit.
2. Pull the documentation. Confirm the recorded time, days, or duration and whether it clearly supports what was billed.
3. If you billed more than the record supports, submit a corrected claim (frequency/resubmission code 7 in box 22 with the original reference number) with the correct code, time tier, or units.
4. If the record supports the billed length, file a reconsideration or appeal. Include the notes, time logs, authorization, and a short letter that ties the documentation to the payer’s policy.
5. For inpatient or facility stays, check whether the payer’s concurrent review denied specific days, and follow its peer-to-peer or clinical appeal process.
6. Write off the adjustment only after the appeal window closes or the appeal is lost. Do not bill the patient for a CO amount.

How to prevent it

• Document start and stop times for every timed service, not just total minutes.
• Match the time tier to the note before the claim leaves, especially for extended sessions and add-on time codes.
• Track authorized days and sessions and request extensions before the approved length runs out. See authorization and referral denials.
• Know each payer’s duration policies and keep them handy for clinicians and coders.
• Monitor CO-152 by provider and service to spot documentation habits that keep triggering reductions. ERA Analyzer can surface these patterns across remittances.

Specialty notes

Behavioral health sees CO-152 most often on time-based psychotherapy and on residential or partial hospitalization days. Therapy providers (PT/OT/SLP) may see it when an episode of care runs longer than the payer’s plan of care approval.