Denial code · group OA
OA-23: Informational only, the part of the charge an earlier payer already paid or adjusted
Short answer
OA-23 is not a denial. A secondary payer uses it to show the part of the charge the primary already paid or wrote off, and X12 allows reason code 23 only with group OA, so a remit that shows CO-23 has the wrong group. It is informational and is not posted, because the primary's payment and write-off are already on the account. It needs work only when the primary's figures on the secondary claim were wrong.
Look up other codes in the denial code library.
Last reviewed by the Remitwright billing team. Editorial policy
Group OA means other adjustment. The number is the reason; the two-letter group says who carries the balance.
Common causes
Normal coordination of benefits
The secondary payer starts from your charge, removes what the primary paid and what the primary adjusted, and pays its share of what is left under its own rules. The OA-23 line reports that removal. On a correctly processed claim there is nothing to fix and nothing to post.
The remit shows it under group CO
X12 limits reason code 23 to group OA. A remit that shows CO-23 has the wrong group on the right reason. If your posting rules write off every CO line automatically, that line posts a second write-off of money the primary already paid or adjusted, and the account drops into a false credit balance.
The primary's figures reached the secondary wrong
The secondary claim carried the primary's allowed amount in the paid field, the patient responsibility was reported as a contractual adjustment, or the adjustment group codes were swapped. The secondary's OA-23 then overstates or understates what the primary actually did.
A lesser-of or non-duplication method you did not expect
Many plans pay no more than their own allowed amount minus what the primary paid, which can leave a zero or near-zero payment and a large OA-23. That is the plan's method, not an error, and the contract or plan document is where you confirm it.
The secondary ignored its own fee schedule
When the secondary's allowed amount on the 835 is lower than the contracted rate, the OA-23 is correct but the payment is short. The CO-45 and paid amounts on the same line are where the problem shows.
The crossover carried the wrong primary data
On automatic crossover claims the primary's adjudication goes to the secondary directly. If the primary later reprocessed, the secondary's OA-23 is based on the first version and needs to be refreshed.
How to fix it and resubmit
- 1
Balance the line before anything else
Charge equals paid plus every CO, PR and OA amount on the 835. If it balances and the secondary's paid amount matches the plan's method, post the secondary's payment, do not post the 23 amount, and move the remaining PR to the patient.
- 2
Compare the CAS data you sent to the primary's 835
Open the secondary 837P and check that the primary's paid amount, contractual adjustment and patient responsibility went into the right segments with the right group codes. A keying error here is fixed with a corrected secondary claim, frequency code 7, carrying the right figures.
- 3
Check the secondary's allowed against your contract
If the allowed on the secondary 835 is below the contracted rate, the shortfall is a payment dispute with the secondary, worked the same way as a CO-45 underpayment, with the contract page and both 835s.
- 4
Refresh after a primary reprocessing
When the primary pays again, send the secondary a corrected claim with the new adjudication so its OA-23 and payment are recalculated. Do not post the difference to the patient.
- 5
Keep the 23 amount off the patient statement
That amount is the primary's payment and write-off, and both are already on the account. The patient owes only what the final payer in the chain reports as PR, and only what your agreements with the payers allow you to collect.
How to prevent it
- Secondary claims generated from the posted primary 835 so the CAS segments carry the primary's figures without rekeying
- Posting rules that require every 835 line to balance before it is saved, with reason code 23 mapped to a non-posting informational adjustment and never to patient responsibility, whichever group code the payer sent
- Expected-payment logic for secondary claims using each plan's coordination method, so a zero payment is flagged only when it is wrong
- A monthly review of secondary claims with zero payment and an OA-23 line, checked against the plan's method and contract rate
An OA-23 on a physical therapy secondary claim
A physical therapy clinic charges 100 for a timed therapy line. The primary plan allows 80, pays 64 and leaves 16 as PR-2 coinsurance, with CO-45 of 20. The secondary plan allows 70 and pays up to its allowed minus what the primary paid, so it pays 6. Its 835 shows paid 6, OA-23 of 84 (the primary's 64 payment plus its 20 adjustment) and PR-2 of 10. The line balances: 6 plus 84 plus 10 equals 100. The poster posts the secondary's 6 payment, does not post the 84 (the primary's 64 and 20 are already on the account), and bills the patient 10, not 16. This is a hypothetical example.
Official text: the X12 claim adjustment reason code list. The meaning above is our paraphrase for billers; the list is the authority.
FAQ
Questions about OA-23
Is OA-23 a denial?
My remit shows CO-23, not OA-23. Does that change anything?
Why did the secondary pay almost nothing and show a big OA-23?
Can I bill the patient the OA-23 amount?
What if the primary reprocesses the claim after the secondary paid?
How do I tell an OA-23 problem from a CO-45 problem?
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