How do I fix or resolve code 55?

Obtain the payer's clinical policy or formulary document for the denied service to understand the specific criteria used to classify it as experimental or investigational. Gather peer-reviewed clinical literature, professional society guidelines, and FDA documentation that support the efficacy and medical necessity of the service for the patient's specific condition. File a formal appeal with a detailed letter of medical necessity, the clinical evidence, and references to the payer's own policy criteria that may be met with additional documentation. If the service is part of an FDA-approved clinical trial, include the trial registration and protocol documentation to support the appeal. If the appeal is denied, escalate to external review (independent review organization) where an independent clinical reviewer assesses the medical necessity and experimental designation; many states require payers to honor external review decisions.

55Denial CodeGeneral Adjustment

Code 55

Problem Description

Procedure/treatment/drug is deemed experimental/investigational by the payer. Usage: Refer to the 835 Healthcare Policy Identification Segment (loop 2110 Service Payment Information REF), if present.

Root Cause

The procedure, treatment, or drug was denied because the payer deemed it experimental or investigational. Payers maintain clinical policies and formularies that classify services as experimental, investigational, or not yet proven effective based on clinical evidence, FDA approval status, and professional society guidelines. Common examples include off-label drug use, emerging surgical techniques, clinical trial interventions, and high-cost specialty drugs not yet on the payer's formulary. The payer applies these policies to deny services that lack sufficient evidence of efficacy, even if the provider believes the service is medically necessary.

Resolution Steps

1Obtain the payer's clinical policy or formulary document for the denied service to understand the specific criteria used to classify it as experimental or investigational.
2Gather peer-reviewed clinical literature, professional society guidelines, and FDA documentation that support the efficacy and medical necessity of the service for the patient's specific condition.
3File a formal appeal with a detailed letter of medical necessity, the clinical evidence, and references to the payer's own policy criteria that may be met with additional documentation.
4If the service is part of an FDA-approved clinical trial, include the trial registration and protocol documentation to support the appeal.
5If the appeal is denied, escalate to external review (independent review organization) where an independent clinical reviewer assesses the medical necessity and experimental designation; many states require payers to honor external review decisions.

EHR Documentation Note

Claim denied 55 — experimental/investigational service; reviewed payer clinical policy, gathered supporting literature, and filed appeal with medical necessity documentation.

Preventative Action

Verify coverage status for experimental or emerging treatments before service delivery and obtain pre-authorization with clinical evidence packages for services likely to be classified as investigational.

Related Codes in General Adjustment

Deductible Amount

Coinsurance Amount

Co-payment Amount

The procedure/revenue code is inconsistent with the patient's age. Usage: Refer to the 835 Healthcare Policy Identification Segment (loop 2110 Service Payment Information REF), if present.

This directory provides reference information only and does not constitute official legal, medical, or financial billing advice. Always consult the payer's official remittance advice and current coding guidelines.