Learn
Out-of-network underpayments
Sometimes the claim is paid, just not enough. Insurers often hire third-party repricers to cut what they pay for out-of-network care. Here is how to recognize it and push back.
When you go out of network, your insurer decides how much of the bill it will allow. To lower that number, many plans send the claim to a third-party repricer that recalculates the payment, often well below the billed charge. The good news: a low payment is not the final word. You can appeal.
Signs your claim was repriced
- A CO-45 adjustment code on your Explanation of Benefits (EOB).
- Language like reference-based pricing or a repricer name (Zelis, MultiPlan, Claritev, Data iSight).
- An allowed amount that is far below what the provider billed.
The approach
How to appeal an underpayment
- 1
Identify the repricer
Read your EOB for a CO-45 adjustment, references to "reference-based pricing" or a repricer name (Zelis, MultiPlan, Claritev, or Data iSight), and an allowed amount far below the billed charge.
- 2
Appeal the insurer, not the vendor
The repricer only makes a recommendation. Your insurer made the payment decision, so your appeal goes to the plan, citing your benefits and the usual, customary, and reasonable rate for the service.
By repricer
Repricer-specific guides
The signs and the paperwork differ a little by vendor. Start with the one named on your EOB.
Zelis
Spot Zelis repricing on your EOB and run the two-step appeal to recover the underpayment.
Read guideMultiPlan / Claritev
Per-platform guidance for MultiPlan and Claritev out-of-network underpayments.
Read guideData iSight
Why you appeal the insurer rather than the vendor when challenging a Data iSight repricing.
Read guideKeep reading
Related guides
ERISA appeals (employer plans)
Most OON underpayment appeals run through your plan, often under ERISA rules.
ReadWhich appeal do I need?
Compare appeal types side by side.
ReadAppeal deadlines
The filing windows that apply to your appeal.
ReadAppeals glossary
Plain-English definitions of ERISA, IDR, QPA, SPD, and the rest.
ReadDisclaimer
This guide is for informational purposes only and does not constitute legal or medical advice. Appeal It Now provides administrative support and appeal preparation services only; we are not a law firm. Please consult a qualified professional for advice specific to your situation.
As of May 2026