OA-23 denial code
The amount reflects what a prior payer already did with this claim. You see this on secondary claims: it is the primary insurer's payment and adjustments being carried over, not a new decision by the secondary. It is arithmetic, not a denial.
OA — Other Adjustment. An adjustment that is neither a contractual write-off nor patient responsibility.
Why you got it
- 1The claim was processed as secondary, and the primary's payment plus its adjustments account for this amount.
- 2A Medicare crossover claim reached the supplemental payer with Medicare's adjudication attached.
How do I fix a OA-23 denial?
- Usually nothing. Check the math: the secondary's allowed amount, minus what the primary paid and adjusted, should equal what the secondary handled. OA-23 is the carried-over piece.
- Do not bill the patient for the OA-23 amount. It was already resolved — paid or written off — at the primary. The patient's actual share is whatever the remit assigns to PR codes.
- If the primary's payment shown here doesn't match the primary's own remit, the secondary processed from bad numbers — send them the primary EOB and ask for reprocessing.
How to stop the next one
Nothing to prevent. Expect it on every secondary claim, and make sure your posting rules don't treat it as a balance to chase. The CO-23 variant means the same carried-over adjudication, grouped as contractual.
Our diagnosis scrubber will not catch this one. OA-23 is driven by procedure codes, modifiers, or eligibility rather than by the diagnosis set — and procedure-side checking needs CPT codes, which aren’t included yet. We would rather tell you that than sell you a tool that quietly misses your most common denial.
If denials like this are a volume problem rather than a one-off, the denial management page explains how the paid workspace catches the coding causes on every claim, and the free ICD-10-CM lookup shows the coding notes behind any diagnosis code on the remittance.