Notes on payer behavior
OA-23 on a remittance: the prior payer's adjudication, and where secondary claims go wrong
Remittance code OA-23 is the payer saying: "The impact of prior payer(s) adjudication including payments and/or adjustments. (Use only with Group Code OA)" What that means for your practice, and whether it's worth chasing, below.
What the payer is saying
OA-23 is the one code on this list that isn't a denial. When a secondary payer processes a claim, it has to show why it isn't paying the full charge, and part of the answer is "the primary already dealt with this much." OA-23 is that line: the primary's payment plus the primary's contractual adjustment, netted into one amount so the secondary's own allowed amount and payment can be shown against what's left. The group code is OA, other adjustment, because the amount isn't the practice's write-off and isn't the patient's bill. It's bookkeeping.
Why it deserves a page anyway
Because the arithmetic behind it is where secondary claims lose money, and because posting software usually treats the whole OA-23 amount as a write-off and moves on. Three things to check when a secondary remittance carries OA-23:
- Did the secondary see the right primary numbers? The claim carried the primary's paid amount and adjustments in the COB loops. A typo there, or a primary remittance that was reprocessed after the secondary claim went out, produces an OA-23 that doesn't match reality and a secondary payment that is short.
- Which secondary method applied? Plans coordinate differently. Some pay up to their own allowed amount less what the primary paid; some pay the patient's remaining responsibility up to their allowed amount; some pay nothing if the primary's payment already exceeded their allowed. The method is in the plan, and a secondary that used the wrong one underpays quietly. Florida Blue, as secondary, caps combined payments at "100 percent of the rates agreed upon in the provider agreement." Its COB rules.
- Is the patient balance right? After OA-23 and the secondary's own adjustments, what's left as PR should be the patient's true remaining responsibility. If the secondary shifted the primary's contractual adjustment to the patient, that's a group-code error, and the patient will be billed for money nobody owes.
Is there anything to recover?
Sometimes. The recoverable cases are the secondary that received wrong primary data (resubmit the secondary claim with the corrected primary remittance attached), the secondary that applied the wrong coordination method (a reconsideration citing the plan's COB provision), and the secondary claim that was never sent at all because the primary's remittance closed the account at zero. That last one is the most common. Why a zero balance isn't the same as paid in full.
The clock on secondary claims
On Florida fully insured business the statute guarantees at least 90 days after the primary's final determination to file the secondary claim, and payers cannot set a shorter window. Florida Blue's manual gives no separate secondary window; it says to file after the primary finalizes with the primary's remittance attached. Diary the 90 days from the primary remittance date, per patient, and the secondary claims stop dying of neglect. The statutory filing floors.
Questions people ask about OA-23
What does OA-23 mean on an EOB?
It is the secondary payer's accounting for what the primary payer already paid and adjusted on the claim. It is not a denial and it is not patient responsibility; it is the amount already dealt with by the prior payer, shown so the secondary's own payment can be reconciled.
Can I bill the patient for an OA-23 amount?
No. OA-23 represents the primary payer's payment and contractual adjustments. The patient's responsibility, if any, appears separately as PR amounts after the secondary has processed.
Why is my secondary payment lower than expected?
Check three things: whether the secondary received the correct primary payment and adjustment figures, which coordination-of-benefits method the plan applies, and whether the primary's remittance was later reprocessed. Any of the three produces a short secondary payment that can be resubmitted or reconsidered.