CO-303Contractual ObligationPatient Responsibility
CO-303 Denial Code: QMB — prior payer's cost-sharing not billable
Qualified Medicare Beneficiary protection: Medicare cost-sharing for QMB patients can't be collected from the patient; Medicaid rules govern what (little) is payable.
Why CO-303 happens
- ●Deductible/coinsurance billed toward a QMB-protected patient
How to fix a CO-303 denial
- 1
Bill the state Medicaid program per its crossover rules; write off the rest
- 2
Refund any amounts collected from the patient — QMB billing violations carry penalties
How to prevent it
Flag QMB status from eligibility responses and suppress patient statements automatically.
Drowning in CO-303 denials?
OakClaim works every denial within 48 hours and builds prevention rules so they stop recurring.