CO-146 — Diagnosis invalid for the date of service
Claim-adjustment reason code 146 · typically reported as CO-146
What it means
The dx code wasn’t valid (or wasn’t yet/no longer active) on the DOS — usually an ICD-10 annual-update miss.
Why DME claims hit it
- October 1 ICD-10 updates not loaded into billing templates
- Truncated dx codes missing required specificity characters
How to fix it
- Validate the dx against the ICD-10 set in force on the DOS; update templates each October
Appeal posture
No — correct and resubmit.
Related denial codes
CO-11 — Diagnosis inconsistent with the procedureCO-9 — Diagnosis inconsistent with patient ageCO-167 — Diagnosis not covered
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