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N789 Remark Code: Clinical Trial Not a Covered Benefit

N789 means clinical trial participation is not a covered benefit under the patient's plan. The payer denied services it identified as part of a clinical trial because the plan does not cover them.

Quick facts

Code
N789 (RARC N789)
Status
Active In use since July 1, 2017.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • PR (Patient Responsibility): The plan treats the service as a non-covered benefit, which may make it patient responsibility if the patient was informed and agreed in advance.
  • CO (Contractual Obligation): The provider absorbs the cost, for example when the contract or trial agreement bars billing the patient.
Official description
Clinical Trial is not a covered benefit.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N789 means

N789 is a benefit-level denial: the plan excludes clinical trial care. The payer recognized the service as trial-related, for example from trial modifiers, a trial diagnosis code, or a registry number, and denied it under that exclusion.

It usually pairs with CARC 96, CARC 204, or CARC 55. Read it alongside the plan type. Many plans must cover routine patient costs in qualifying trials, so an N789 on such a plan may deserve a challenge.

Common causes

  • The plan is exempt from clinical trial coverage requirements, such as some grandfathered plans.
  • The trial does not meet the plan’s or the law’s definition of a qualifying trial.
  • Investigational items or research-only services were billed to the plan.
  • Routine care was flagged as trial care and swept into the exclusion.

What to do

  1. Confirm the patient’s plan type and whether clinical trial coverage rules apply to it.
  2. Separate routine costs from investigational items and research-only services, which the sponsor usually funds.
  3. If routine costs were denied on a plan that should cover them, appeal with trial documentation and the relevant coverage rule.
  4. Check the clinical trial agreement for sponsor-paid items and bill the sponsor where applicable.
  5. Review informed consent and financial agreements before billing the patient.

How to prevent it

Have research billing staff review each trial participant’s coverage before enrollment and set up a billing plan that separates sponsor-paid, plan-billable, and patient costs.

Codes that may appear with N789

  • CO-96 (Non-covered charge(s).): A non-covered charge, explained by the plan's clinical trial exclusion.
  • PR-204 (This service/equipment/drug is not covered under the patient's current benefit plan): The service is not covered under the patient's current benefit plan.
  • CO-55 (Procedure/treatment/drug is deemed experimental/investigational by the payer.): The procedure or treatment is considered experimental or investigational.
  • N721 (This service is only covered when performed as part of a clinical trial.): The opposite rule: the service is covered only when performed as part of a clinical trial.
  • MA50 (Missing/incomplete/invalid Investigational Device Exemption number or Clinical Trial number.): The investigational device exemption or clinical trial number is missing or invalid.
  • M61 (We cannot pay for this as the approval period for the FDA clinical trial has expired.): The FDA clinical trial approval period has expired.

N789 FAQ

Don't laws require coverage of clinical trial costs?

Federal law requires many health plans to cover routine patient costs for qualifying trials, and Medicare covers routine costs in qualifying trials. Exceptions exist, such as some grandfathered plans. Review the plan type before accepting N789.

What costs does 'routine' cover?

Generally the care the patient would receive anyway, not the investigational item itself or research-only tests, which are usually funded by the study sponsor.

Who pays if the plan does not?

Depending on the trial agreement and informed consent, the sponsor may cover certain costs, or the patient may be responsible. Check both documents before billing anyone.