A Medical Review Officer (MRO) is a person who is a licensed physician and who is responsible for receiving and reviewing laboratory results generated by an employer’s drug testing program and evaluating medical explanations for certain drug test results.

As a MRO, you act as an independent and impartial “gatekeeper” and advocate for the accuracy and integrity of the drug testing process. You provide quality assurance review of the drug testing process for the specimens under your purview, determine if there is a legitimate medical explanation for laboratory confirmed positive, adulterated, substituted and invalid drug test results, ensure the timely flow of test result and other information to employers and protect the confidentiality of the drug testing information.

Applicable Regulations

Like all other service providers, you perform an important function in the DOT safety program, as such, it is important for you to fully understand the regulations. Therefore, the MRO should familiarize him/herself with 49 CFR Part 40 while paying particular attention to the following:

  • Subpart G – Medical Review Officer and the Verification Process
  • Subpart H – Split Specimen Tests
  • Subpart I – Problems in Drug Tests
  • Subpart P – Confidentiality and Release of Information
  • Subpart Q – Roles and Responsibilities of Service Agents
  • Subpart R – Public Interest Exclusions
  • Appendix D to Part 40-Report Format: Split Specimen Failure to Reconfirm


  • Federal Custody and Control Form

    • Revised CCF (August 2020)
    • Instructions for completing the CCF (August 2020)
    • eCCF Notice
    • List of labs with approved Electronic Custody and Control Form (eCCF) systems
  • Medical Review Officers Contacting Employee’s Treating Physician
  • Program Reminder for MROs, TPAs, Collectors, and Employers
  • Reminder to Medical Review Officers (MRO) – Verifying an Employee’s Prescription
  • DOT’s 10 Steps to Collection Site Security and Integrity Video
  • Mock Collection Instructional Video
  • Part 40 Q&As

Association/Industry links

  • American Association of Medical Review Officers
  • American College of Occupational and Environmental Medicine (ACOEM)
  • American Society of Addiction Medicine
  • Medical Review Officer Certification Council
  • National Drug & Alcohol Screening Association
  • Substance Abuse Program Administrators Association