CO-22 — Another payer may be responsible (coordination of benefits)
Claim-adjustment reason code 22 · typically reported as CO-22 or OA-22
What it means
The payer’s records say someone else is primary — it wants the other payer’s adjudication first.
Why DME claims hit it
- Working-aged patient with employer group coverage primary to Medicare
- Auto/liability or workers’ comp open on file for the dx billed
- Stale COB data after the patient lost other coverage
How to fix it
- Run the COB/MSP questionnaire with the patient; update the payer’s COB records (for Medicare, via the BCRC)
- Bill the true primary, then resubmit with the primary EOB attached
Appeal posture
Resolve the COB record — appeals don’t fix coordination data.
Related denial codes
OA-23 — Prior payer’s adjudication impactCO-109 — Wrong payer / contractor for this claimPR-31 — Patient cannot be identified as insured
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