If you work in medical billing, you’ve probably run into Denial Code OA 23 more often than you’d like. It appears when a secondary payer adjusts a claim based on what the primary payer has already covered or modified. This happens frequently in multi-insurance situations where coordination of benefits becomes unclear. These denials stack up fast.
According to Premier’s survey, nearly 15 % of claims submitted to private payers are initially denied, and providers incur about $19.7 billion annually in costs merely to review and appeal those denials.
What makes OA 23 challenging is how easily it slips in when payers receive mismatched information. Even small gaps in policy details, patient coverage updates, or primary payment data can derail an otherwise clean claim. Teams that understand what triggers OA 23 can correct it quickly, prevent repeat issues, and maintain steady reimbursement.
Table of Contents
What Is Denial Code OA 23?
Denial Code OA 23 is used when a claim is adjusted because another insurer has already processed part of the payment. It appears most often in coordination of benefits (COB) situations, where payers need the correct order of insurance coverage before issuing payment.
The code has two parts that explain the reason behind the denial.
Group Code OA is a Claim Adjustment Group Code for Other Adjustment, which tells you the issue is not tied to patient responsibility or contractual write-offs.
Reason Code 23 is a Claim Adjustment Reason Code that indicates the payer cannot continue until it verifies what the primary insurer paid or adjusted.
When OA 23 shows up, it means the secondary payer needs accurate details from the Explanation of Benefits (EOB) issued by the primary plan. The denial usually resolves once the correct insurance sequence, policy information, and primary payment amounts are confirmed and the claim is resubmitted with the complete secondary details.
Common Causes of Denial Code OA 23
OA 23 denials typically happen when the payer cannot verify insurance order or primary payment details. Most issues fall into a small set of predictable patterns.
1. Incorrect insurance sequence
- Primary and secondary plans listed in the wrong order
- Medicare marked as primary when commercial should be
- COB updates not captured during registration
2. Missing primary EOB (Explanation of Benefits)
- EOB not attached during secondary claim submission
- EOB uploaded with missing line items or mismatched amounts
- Delays when the EOB is still pending from the primary payer
3. Outdated policy information
- Old employer coverage still active in the system
- New plan effective dates not updated
- Policy terminated but still billed as active
4. Coverage changes not communicated
- Patients switching plans mid-year
- Coordination of benefits questionnaires not completed
- Spouse or dependent coverage updated but not documented
5. Data mismatches in claim details
- Incorrect subscriber ID
- Wrong group number
- Demographics that do not match what the primary payer has on file
6. Dual-coverage patients with no COB updates
- High-risk category for recurring OA 23 denials
- Common in workers’ comp, auto liability, and employer plan transitions
How to Identify OA 23 Denials in Your System
Use this section as a quick diagnostic guide. The goal is to help teams spot OA 23 fast without digging through multiple reports.
1. Start with your ERA or EOB
Look for:
- Group Code: OA
- Reason Code: 23
These appear together and confirm the payer adjusted the claim due to primary payment activity.
2. Check your denial work queue
OA 23 often shows up under:
- “Coordination of Benefits”
- “Secondary claim pending primary info”
- “Other Adjustment”
A sudden cluster in this queue usually points to missing or outdated COB details.
3. Review payer remark codes
Payers may phrase OA 23 differently. Common variations include:
- “Primary payment required”
- “COB information incomplete”
- “Submit with primary EOB”
These notes help you understand exactly what the payer needs.
4. Validate insurance sequence in the patient profile
Quick checks:
- Is the correct plan marked as primary
- Are the effective dates correct
- Has the patient updated benefits recently
Incorrect sequencing is one of the fastest ways OA 23 appears.
5. Look for recurring patterns
You may notice:
- Specific employer plans triggering most OA 23s
- Medicare secondary cases stacking in aging
- Patients with dual coverage repeatedly denied for COB
These patterns help you take proactive action.
How to Fix Denial Code OA 23?
Start by confirming the correct insurance order in the patient’s record. Make sure the primary, secondary, and any tertiary plans are sequenced accurately, and verify coverage dates. Incorrect sequencing is the most common reason OA 23 appears, so correcting this upfront prevents repeated denials.
Next, retrieve the complete Explanation of Benefits (EOB) from the primary payer. The secondary payer needs the full breakdown, including the payment amount, adjustments, and patient responsibility. Claims missing even one of these details will stall in OA 23.
Once the EOB is available, compare it with the original claim. Match billed units, allowed amounts, and patient demographics. Even small inconsistencies can prevent the secondary payer from processing the claim. Correct any discrepancies before resubmitting.
Update the patient’s coordination of benefits information to reflect the most current policyholder details and plan hierarchy. This step is essential for accounts with dual coverage, where outdated information causes repeat denials.
After the corrections are complete, resubmit the claim to the secondary payer with the full primary EOB attached. Include any payer-specific notes or required documentation to support the updated submission. Most secondary payers will process the claim smoothly once the COB details are clear.
Finally, monitor the claim until payment posts. Use your denial queues and secondary aging reports to ensure the claim moves forward without hitting timely filing limits. Document the correction so your team has a clear reference for future account reviews and audits.
Preventive Measures to Reduce OA 23 Denials
A strong prevention plan keeps OA 23 from turning into a recurring drain on revenue. The goal here is to build consistency across documentation, coding, and claim review so errors are corrected before the claim reaches the payer.
Strengthen Staff Competency
Regular training helps teams stay current on documentation rules, payer updates, and COB requirements. Even small gaps in understanding can lead to recurring OA 23 denials, so periodic refreshers ensure accuracy at the source.
Adopt Automated Verification Tools
Claim scrubbing and eligibility verification tools help catch issues like missing COB details, outdated policy information, and coding inconsistencies. These tools flag high-risk claims early, reducing the chance of rework later.
Run Internal Quality Audits
Routine audits make it easier to spot patterns behind OA 23 denials. Reviewing sampled claims each month can reveal gaps in workflows, documentation steps that staff may be skipping, or payer-specific rules that need updates in your process.
Financial and Operational Impact of OA 23 Denials
OA 23 denials may seem like routine adjustments, but they slow things down in ways most teams feel quickly. Payments get pushed out, staff work gets interrupted, and revenue cycles start to drag.
Snapshot of the Impact
| Area Affected | What Happens |
| Cash Flow | Secondary payments take longer to arrive and move into aging buckets. |
| Workload | Teams spend extra hours sorting through EOBs, fixing COB details, and resubmitting claims. |
| Revenue Risk | Longer delays raise the chance of partial payments or write-offs. |
| RCM Efficiency | A high volume of OA 23s usually points to gaps in benefit coordination. |
When these issues stack up, they create uneven payment patterns and add pressure on already busy billing teams.
The takeaway: consistent monitoring and quicker resolution of OA 23 reduce operational drag and protect overall financial stability.
Denial code OA 23 is one of those issues that signals deeper gaps in coordination of benefits, eligibility checks, and data accuracy. When it isn’t managed well, it creates repeat rework, slows reimbursement, and adds pressure on the revenue cycle team. Strengthening denial management workflows is the fastest way to prevent these avoidable COB-related delays and keep claims moving without bottlenecks.AnnexMed supports providers with a denial management approach that blends accurate COB validation, timely follow-up, and clear documentation that aligns with payer rules. As an end-to-end revenue cycle management partner, our team helps prevent OA 23 denials at the source while resolving existing backlogs with clean, corrected claims. It’s a streamlined path to fewer adjustments, better cash flow, and more predictable reimbursement.
Denials won’t fix themselves, but they can be prevented.
Discover how AnnexMed’s denial management team identifies root causes and strengthens your reimbursement pipeline.
FAQs
OA 23 often shows up when the secondary payer can’t match the primary payment details to the claim. Even if the primary has paid, missing EOB data, outdated COB information, or incorrect sequencing can trigger the denial.
Yes. Delays in retrieving the primary EOB or correcting COB details can push claims close to timely filing limits, increasing the risk of write-offs. Quick follow-up and clean documentation help avoid this.
You’ll need the primary payer’s full EOB, updated COB details, and accurate plan sequencing. These pieces confirm payment activity and allow the secondary payer to process the claim correctly.
Patients with two active plans often experience coverage changes, employer updates, or outdated coordination records. If these aren’t captured during registration, OA 23 becomes a recurring issue.
Yes. Eligibility verification tools, automated COB checks, and claim scrubbers help flag missing or inconsistent data before submission, reducing the chance of secondary payers issuing OA 23 denials.
