MRO Practice Exam 2026/2027 | 300+ Practice Questions, Answers &
Detailed Rationales | DOT 49 CFR Part 40
Section 1: MRO Fundamentals and DOT Framework
1. What is the primary function of a Medical Review Officer (MRO) in a DOT
drug-testing program?
A. Collect urine specimens
B. Independently review and verify laboratory-confirmed results
C. Decide employee disciplinary action
D. Perform laboratory analysis
Answer: B. Independently review and verify laboratory-confirmed results
Rationale: The MRO provides an independent medical review of laboratory-
confirmed non-negative results and determines whether there is a legitimate
medical explanation under the applicable DOT rules.
2. Which regulation is central to DOT workplace drug-testing procedures?
A. 29 CFR Part 1910
B. 49 CFR Part 40
C. 42 CFR Part 482
D. 45 CFR Part 46
Answer: B. 49 CFR Part 40
Rationale: 49 CFR Part 40 establishes procedures for transportation workplace
drug and alcohol testing, including MRO responsibilities.
3. What does MRO stand for?
A. Medical Regulation Officer
B. Medical Review Officer
C. Medical Reporting Organization
D. Medical Records Official
Answer: B. Medical Review Officer
,Rationale: An MRO is a licensed physician responsible for reviewing and verifying
certain laboratory drug-test results.
4. Which party generally communicates a verified drug-test result to the
employer's designated representative?
A. Laboratory technician
B. Collector
C. MRO
D. Employee assistance counselor
Answer: C. MRO
Rationale: In the DOT process, the MRO reviews the laboratory result and
communicates the verified result as required to the Designated Employer
Representative (DER).
5. What does DER mean?
A. Drug Evaluation Reviewer
B. Designated Employer Representative
C. Departmental Examination Registrar
D. Designated Evidence Recorder
Answer: B. Designated Employer Representative
Rationale: The DER is the employer's authorized representative responsible for
receiving and managing certain DOT testing information.
6. Which professional must perform the MRO function in a DOT program?
A. Any laboratory scientist
B. Any registered nurse
C. A qualified physician meeting applicable MRO requirements
D. Any human-resources employee
Answer: C. A qualified physician meeting applicable MRO requirements
Rationale: DOT MRO responsibilities require a physician who satisfies the
regulatory qualification and training requirements.
,7. What is the purpose of an MRO interview?
A. To determine an employee's salary
B. To identify a legitimate medical explanation for a laboratory result
C. To determine whether a collector followed every workplace policy
D. To provide legal representation to the employee
Answer: B. To identify a legitimate medical explanation for a laboratory result
Rationale: The interview allows the MRO to obtain relevant medical information,
including medication and treatment information that may explain a laboratory
result.
8. Which document is commonly associated with documenting custody and
control of a DOT specimen?
A. CCF
B. OSHA 300
C. SDS
D. W-4
Answer: A. CCF
Rationale: The Federal Custody and Control Form (CCF) documents the collection,
transfer, testing, and reporting of a DOT specimen.
9. Why is chain of custody important?
A. It determines employee seniority
B. It documents specimen handling and accountability
C. It establishes the employee's medical diagnosis
D. It determines the laboratory's profit
Answer: B. It documents specimen handling and accountability
Rationale: Chain-of-custody documentation helps establish the identity and
integrity of the specimen throughout the testing process.
10. Which organization administers the DOT transportation workplace testing
framework?
, A. Department of Transportation
B. Department of Agriculture
C. Department of Education
D. Department of Commerce
Answer: A. Department of Transportation
Rationale: DOT regulations establish drug and alcohol testing requirements for
covered transportation employees and employers.
11. What is the main distinction between the MRO and the laboratory?
A. The MRO performs all specimen collections
B. The laboratory performs analytical testing, while the MRO conducts medical
review
C. The laboratory decides disciplinary action
D. The MRO manufactures testing equipment
Answer: B. The laboratory performs analytical testing, while the MRO conducts
medical review
Rationale: The laboratory analyzes specimens according to required procedures,
while the MRO interprets confirmed results in the medical-review process.
12. What should an MRO generally avoid doing?
A. Reviewing medication information
B. Verifying legitimate medical explanations
C. Making the employer's disciplinary decision
D. Communicating required results
Answer: C. Making the employer's disciplinary decision
Rationale: The MRO determines and reports test status according to applicable
rules; employment discipline is generally an employer function.
13. What is a laboratory-confirmed positive result?
A. An initial screening reaction only
B. A result supported by required confirmatory analytical testing
Detailed Rationales | DOT 49 CFR Part 40
Section 1: MRO Fundamentals and DOT Framework
1. What is the primary function of a Medical Review Officer (MRO) in a DOT
drug-testing program?
A. Collect urine specimens
B. Independently review and verify laboratory-confirmed results
C. Decide employee disciplinary action
D. Perform laboratory analysis
Answer: B. Independently review and verify laboratory-confirmed results
Rationale: The MRO provides an independent medical review of laboratory-
confirmed non-negative results and determines whether there is a legitimate
medical explanation under the applicable DOT rules.
2. Which regulation is central to DOT workplace drug-testing procedures?
A. 29 CFR Part 1910
B. 49 CFR Part 40
C. 42 CFR Part 482
D. 45 CFR Part 46
Answer: B. 49 CFR Part 40
Rationale: 49 CFR Part 40 establishes procedures for transportation workplace
drug and alcohol testing, including MRO responsibilities.
3. What does MRO stand for?
A. Medical Regulation Officer
B. Medical Review Officer
C. Medical Reporting Organization
D. Medical Records Official
Answer: B. Medical Review Officer
,Rationale: An MRO is a licensed physician responsible for reviewing and verifying
certain laboratory drug-test results.
4. Which party generally communicates a verified drug-test result to the
employer's designated representative?
A. Laboratory technician
B. Collector
C. MRO
D. Employee assistance counselor
Answer: C. MRO
Rationale: In the DOT process, the MRO reviews the laboratory result and
communicates the verified result as required to the Designated Employer
Representative (DER).
5. What does DER mean?
A. Drug Evaluation Reviewer
B. Designated Employer Representative
C. Departmental Examination Registrar
D. Designated Evidence Recorder
Answer: B. Designated Employer Representative
Rationale: The DER is the employer's authorized representative responsible for
receiving and managing certain DOT testing information.
6. Which professional must perform the MRO function in a DOT program?
A. Any laboratory scientist
B. Any registered nurse
C. A qualified physician meeting applicable MRO requirements
D. Any human-resources employee
Answer: C. A qualified physician meeting applicable MRO requirements
Rationale: DOT MRO responsibilities require a physician who satisfies the
regulatory qualification and training requirements.
,7. What is the purpose of an MRO interview?
A. To determine an employee's salary
B. To identify a legitimate medical explanation for a laboratory result
C. To determine whether a collector followed every workplace policy
D. To provide legal representation to the employee
Answer: B. To identify a legitimate medical explanation for a laboratory result
Rationale: The interview allows the MRO to obtain relevant medical information,
including medication and treatment information that may explain a laboratory
result.
8. Which document is commonly associated with documenting custody and
control of a DOT specimen?
A. CCF
B. OSHA 300
C. SDS
D. W-4
Answer: A. CCF
Rationale: The Federal Custody and Control Form (CCF) documents the collection,
transfer, testing, and reporting of a DOT specimen.
9. Why is chain of custody important?
A. It determines employee seniority
B. It documents specimen handling and accountability
C. It establishes the employee's medical diagnosis
D. It determines the laboratory's profit
Answer: B. It documents specimen handling and accountability
Rationale: Chain-of-custody documentation helps establish the identity and
integrity of the specimen throughout the testing process.
10. Which organization administers the DOT transportation workplace testing
framework?
, A. Department of Transportation
B. Department of Agriculture
C. Department of Education
D. Department of Commerce
Answer: A. Department of Transportation
Rationale: DOT regulations establish drug and alcohol testing requirements for
covered transportation employees and employers.
11. What is the main distinction between the MRO and the laboratory?
A. The MRO performs all specimen collections
B. The laboratory performs analytical testing, while the MRO conducts medical
review
C. The laboratory decides disciplinary action
D. The MRO manufactures testing equipment
Answer: B. The laboratory performs analytical testing, while the MRO conducts
medical review
Rationale: The laboratory analyzes specimens according to required procedures,
while the MRO interprets confirmed results in the medical-review process.
12. What should an MRO generally avoid doing?
A. Reviewing medication information
B. Verifying legitimate medical explanations
C. Making the employer's disciplinary decision
D. Communicating required results
Answer: C. Making the employer's disciplinary decision
Rationale: The MRO determines and reports test status according to applicable
rules; employment discipline is generally an employer function.
13. What is a laboratory-confirmed positive result?
A. An initial screening reaction only
B. A result supported by required confirmatory analytical testing
