What does OA-23 denial code mean? Prior payer adjudication explained

OA-23 is a claim adjustment reason code that reports the impact of a prior payer's decision on a claim, which is why it shows up when a second payer processes a claim. Numetix keeps secondary balances visible so they are not lost between payers. This guide explains what OA-23 means, how to read it, and what to do.

QUICK ANSWER: WHAT DOES OA-23 MEAN?

• OA-23 reports how a prior payer's decision, including its payments and adjustments, affected the amount a later payer handles.

• X12 says the reason code is used only with group code OA, which CMS defines as other adjustments when no other group code applies.

• Read it as information about the earlier payer's decision, check the secondary payment math, and follow up only if the balance is wrong.

Numetix is the expert-led, AI-powered, human-in-the-loop bookkeeping layer for medical and dental practices, so remittances, adjustments, and receivables are reconciled by software and reviewed by a named person. The sections below explain the code, the causes, and the steps to fix and prevent it.

What does OA-23 mean?

The X12 list describes code 23 as the impact of prior payer adjudication, including payments and adjustments, and says to use it only with group code OA (X12 claim adjustment reason codes). CMS defines OA as other adjustments, used when no other group code applies to the adjustment (CMS Medicare Claims Processing Manual, chapter 22). That pairing explains the label: OA-23 is the only valid combination, and it is informational about what an earlier payer did.

Why does OA-23 appear on a claim?

How do you read OA-23 on a secondary claim?

1. Find the primary remittance and note its payment, adjustments, and patient responsibility.

2. Compare those figures with the amount the secondary payer shows for the prior payer.

3. Check the secondary payer's own calculation against its contract and the plan rules.

4. Identify what balance, if any, remains and who owes it.

5. Post the payment and adjustments, and move any patient amount to the patient account.

Our guides to CARC denial codes and RARC remark codes explain the code families, and timely filing denials matter when secondary claims wait on a primary payment.

How should OA-23 appear in your books?

• Post the primary payment first, then the secondary, so each remittance ties to its own deposit.

• Record the adjustments in the right accounts, as the contractual adjustment and write-off glossary entries explain.

• Do not write off a remaining balance until both payers have finished.

• Keep a note of the prior payer's decision on the claim for later audits.

How do you prevent secondary billing problems?

• Record the order of benefits at registration and verify it each visit.

• Send the primary remittance with the secondary claim whenever the payer asks for it.

• Track secondary claims separately so they do not age unnoticed.

• Review unpaid secondary balances weekly.

Frequently asked questions

Is OA-23 a denial?

Not by itself. It is an adjustment reason code that describes the impact of a prior payer's decision on the claim. It often appears on secondary claims alongside a payment or another code. Read the whole remittance, because any denial will be explained by other codes on the same line.

Does OA-23 mean I should write off the balance?

No. OA-23 is informational and tells you what an earlier payer did. Do not write off a balance because of it. Check the primary and secondary remittances, confirm what remains, and bill the patient or the next payer only when the plan rules and your contract allow it.

Can OA-23 appear on a primary claim?

It describes prior payer adjudication, so it normally relates to claims with an earlier payer. If you see it on what you believe is a primary claim, check the order of benefits and the coverage on file, because the payer may be treating another plan as primary.

Numetix is the expert-led, AI-powered, human-in-the-loop bookkeeping layer that keeps denials, adjustments, and receivables reconciled with a named reviewer. See our accounting services built for healthcare practices.