OakClaim
CO-55Contractual ObligationMedical Necessity

CO-55 Denial Code: Experimental/investigational procedure

The procedure/treatment/drug is deemed experimental or investigational by the payer.

Why CO-55 happens

  • New technology or off-label use not yet in payer policy
  • Unlisted code without supporting literature

How to fix a CO-55 denial

  1. 1

    Review the payer's medical policy for the service

  2. 2

    Appeal with peer-reviewed evidence, FDA status, and specialty society guidelines

  3. 3

    Use the payer's exception/IRO process for strong cases

How to prevent it

Check medical policy before scheduling novel procedures; obtain waivers.

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