A duplicate claim adjustment has been applied. This is the other adjustment version of CO-18.
Same as CO-18: verify with your provider whether the original claim was paid. If not paid, appeal with documentation of the original submission.
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Bill Advantage can analyze your denial and generate a ready-to-send appeal or dispute letter in minutes.
Open Denial Letter TranslatorDenial codes on your EOB explain why a claim was denied. Learn what the most common codes mean in 2026 and the exact steps to fix or appeal each one.
Read articleWhat to Do When Insurance Denies a ClaimInsurance denied your claim? Learn the exact steps to appeal a health insurance denial in 2026, from reading the denial letter to external independent review.
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