CO-16 denial code
Something is missing or wrong on the claim itself, and the remark code on the line says what.
“Claim/service lacks information or has submission/billing error(s). … At least one Remark Code must be provided …”
Start 01/01/1995 · Last modified 03/01/2018 · X12 adjustment reason code list
What it usually means in behavioral health
CO-16 is a correction, not a clinical decision. Read the remark code first; it names the missing or invalid field.
Facility claims for residential, PHP, and IOP collect CO-16s from fields outpatient billers rarely touch, such as admission dates and hours, occurrence and condition codes, and the rendering or attending provider. Professional claims often miss the rendering NPI or a supervising provider.
Common causes
- Missing or invalid rendering, attending, or supervising provider identifier
- Missing or invalid authorization number (often with M62)
- Invalid procedure code for the date of service
- Missing facility-claim data such as admission date, occurrence codes, or condition codes
- Diagnosis pointer or code format errors
Correct and resubmit, or appeal?
Correct and resubmit. When the remark code is MA130, the claim was unprocessable and carries no appeal rights, so the fix is a new claim with the complete information.
What to do
Read every remark code on the line; each names a field.
Fix the field in the billing system, not just on this claim, so the next one goes out clean.
Resubmit as a new or corrected claim, following the payer's rules for which.
Check that the timely-filing clock is still open.
Often seen with
Got a CO-16 on your desk?
Send us the facts on that one denial — codes, payer, level of care, and dollar amount, no patient information — and within 2 business days we’ll tell you whether to correct or appeal, the deadline to watch, and what evidence would answer it. Free.