OA-23 Denial Code: Prior Payer Adjudication Impact (Secondary Claims)
The OA-23 code shows the impact of a prior payer's adjudication - the payments and adjustments the primary insurance already made - on a secondary or tertiary claim. It is bookkeeping, not a denial: the secondary payer uses OA-23 to account for what the primary already handled before calculating its own payment. Seeing OA-23 on a secondary remit is expected.
Common Causes
- Normal secondary claim processing - the primary's payment and contractual adjustments are reflected as OA-23 on the secondary remit
- Medicare crossover claims processed by a supplemental payer
- Confusion at posting: OA-23 amounts mistakenly posted as new write-offs on top of the primary's adjustments, understating expected revenue
How to Fix OA-23
- Treat OA-23 as informational - it represents amounts the primary payer already paid or adjusted, not a new reduction to work
- Post the secondary payment against the remaining balance; do not double-post the primary's adjustments again from the OA-23 amount
- Verify the primary payment information transmitted correctly - if the OA-23 amount does not match the primary remit, the secondary claim may have carried wrong COB data
- If the secondary paid less than expected, compare its allowed amount and the patient cost-share picked up, rather than disputing the OA-23 amount itself
Frequently Asked Questions
OA-23 reflects the impact of the prior payer's adjudication - what the primary insurance paid and adjusted - on the secondary claim. It is an accounting entry the secondary payer uses to arrive at its own payment, not a denial.
As informational offsets, not new write-offs. The primary's payment and contractual adjustments were already posted from the primary remit; OA-23 on the secondary remit accounts for those same amounts, so posting them again understates collections.
Related Denial Codes
Related Resources
Claim adjustment reason codes and remittance advice remark codes are standardized code sets maintained by X12. The explanations on this page are written in our own words for educational purposes, based on public CMS and Medicare contractor documentation. Payer policies vary - always confirm handling with the specific payer's guidance and your contracts.