CO-181 denial code: procedure code invalid on the date of service

Claim adjustment reason code 181 says: procedure code was invalid on the date of service. The CPT or HCPCS code on the claim wasn't an active code on the date the service was performed.

With group code CO, the patient can't be billed. Correcting the code and resubmitting usually resolves it.

• The code was deleted or replaced. CPT codes change every January 1. HCPCS Level II codes, which include many drugs and supplies, can change every quarter.
• The code was used before its effective date.
• A charge list, template or pick list still has the old code.
• A temporary code expired, as some HCPCS codes are created for a limited period.

1. Look up the code for the date of service in that year's code set.
2. Find the replacement code that describes the service the note documents.
3. Correct the claim and resubmit.
4. Update the charge list and templates, so the old code doesn't go out again.

• Check every procedure code against the date of service before sending.
• Update charge lists and templates before January 1 and before each quarterly HCPCS update.
• Watch drug codes especially, since many are HCPCS codes that change during the year.

CO-181 is a coding problem, so it is caught at billing.

Claira Health's AI agents catch this before the claim goes out, and tell your biller what's wrong in plain English. Your team sees only what needs a decision, and approves every step. On a 20-minute call, we’ll walk through it using one of your own denials.

Related: CO-146, diagnosis invalid for the date. Book a 20-minute call before your next code update.