835 Denial Combination
CO-109
Contractual Obligation · Claim-Level Adjustment
What This Combination Means
The claim was not filed with the patient's primary payer first. Secondary payers require a primary payer EOB before processing.
N/A
Appeal Success
3-10 days
Avg. Resolution
Easy
Difficulty
No
Appealable
Step-by-Step Resolution
Steps tailored specifically to this CO-109 combination — not generic advice.
- 1
Identify the patient's primary insurance from their eligibility record.
- 2
File the claim with the primary payer first.
- 3
Once the primary EOB is received, attach it and file with the secondary payer.
- 4
Update your COB workflow to ensure primary is always filed first.
Specialty Context
How CO-109 typically presents across different practice types.
Dental
Verify the claim was not filed with the patient's primary payer first per your dental plan contract and documentation requirements.
Medical
Confirm the claim was not filed with the patient's primary payer first against payer policy and submit corrected claim as needed.
Behavioral Health
Apply behavioral health parity rules and confirm the claim was not filed with the patient's primary payer first per MHPAEA standards.
Individual Code References
View the standalone definition for each code in this combination.
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