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MA50 Remark Code: Missing IDE or Clinical Trial Number

MA50 means the claim is missing, or has an invalid, Investigational Device Exemption (IDE) number or clinical trial number. Payers need these identifiers to confirm coverage for services connected to an approved device study or clinical trial.

Quick facts

Code
MA50 (RARC MA50)
Status
Active In use since January 1, 1997; last modified March 1, 2014.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The provider must supply the correct identifier. The patient generally should not be billed for a data omission.
Official description
Missing/incomplete/invalid Investigational Device Exemption number or Clinical Trial number.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What MA50 means

Services tied to research are paid only under specific conditions. An investigational device can be covered when it is part of an approved IDE study, and routine costs in qualifying clinical trials may be covered too. To apply those rules, the payer needs an identifier linking the claim to the study. MA50 says that identifier was absent or did not check out.

Common causes

  • The IDE number was not entered for a device furnished under an approved study.
  • The clinical trial registry number was omitted or entered in the wrong format.
  • Trial modifiers or the trial participation diagnosis were used without a trial number.
  • The study was not registered or approved with the payer.

How to fix it

  1. Get the identifiers from the research team: the IDE number and the registry number for the trial.
  2. Confirm the study’s coverage status with the payer, including any approval required before billing.
  3. Enter the identifiers in the fields the payer specifies, along with required modifiers and diagnosis codes.
  4. Resubmit a replacement claim with resubmission code 7 in box 22 if the original was processed.

How to prevent it

Set up a research billing workflow in which the study team flags participants and provides identifiers before claims are released. Coordinating research and billing staff avoids repeated denials; a Claims Validator can check that trial-coded claims include the required number.

Codes that may appear with MA50

  • CO-16 (Claim/service lacks information or has submission/billing error(s).): Information needed to adjudicate is missing, with MA50 pointing to the IDE or trial number.
  • CO-114 (Procedure/product not approved by the Food and Drug Administration.): The procedure or product is not approved by the FDA, which may apply if the device study cannot be confirmed.
  • CO-272 (Coverage/program guidelines were not met.): Coverage or program guidelines were not met.
  • MA53 (Missing/incomplete/invalid Competitive Bidding Demonstration Project identification.): The competitive bidding demonstration identification is missing or invalid, another program identifier.
  • CO-96 (Non-covered charge(s).): A non-covered charge, which can follow if the research service is not covered at all.

MA50 FAQ

Where do these numbers go on the claim?

Medicare's instructions have placed the IDE number in box 23 on paper claims, and the clinical trial number in box 19. Electronic claims use specific reference segments. Check the payer's current instructions.

What else identifies a clinical trial claim?

Medicare also expects trial-related modifiers, such as Q0 or Q1, and a diagnosis code showing participation in a clinical trial, such as Z00.6, along with the trial number.

Does every payer require a trial number?

No. Requirements vary, so confirm each payer's rules for research-related services.