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MEDICAL REVIEW OFFICER (MRO) ACTUAL EXAM
2026/2027 ACCURATE TEST COMPLETE ACTUAL
QUESTIONS AND CORRECT ANSWERS WITH DETAILED
RATIONALES (100% CORRECT VERIFIED SOLUTIONS)
LATEST UPDATED VERSION 2026
1. Which statement best describes the primary role of a Medical Review
Officer (MRO) in the DOT drug-testing program?
A. To determine whether an employer should terminate an employee after a
positive test
B. To independently review laboratory results and evaluate legitimate medical
explanations for certain results
C. To collect every specimen submitted for DOT testing
D. To provide substance-abuse treatment to employees who test positive
Answer: B
Rationale: The MRO serves as an independent and impartial gatekeeper for the
drug-testing process. The MRO reviews laboratory results and evaluates whether a
legitimate medical explanation exists for certain confirmed results. The MRO does
not make employment decisions or function as the employee's treatment provider
merely by serving as MRO.
2. Which professional may qualify as a DOT MRO?
A. Any licensed registered nurse
B. Any pharmacist with toxicology experience
C. A licensed physician who satisfies the applicable qualification and training
requirements
D. Any physician assistant who completes a drug-testing course
Answer: C
Rationale: Under §40.121, an MRO must be a licensed physician—Doctor of
Medicine or Osteopathy—and must satisfy the specified knowledge and
qualification-training requirements.
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3. Which topic is specifically part of the required MRO qualification training?
A. Employee payroll administration
B. Specimen collection procedures
C. Workers' compensation litigation
D. Employer hiring practices
Answer: B
Rationale: MRO qualification training must cover areas including specimen
collection procedures, chain of custody, reporting and recordkeeping,
interpretation of drug and validity-test results, MRO responsibilities,
interaction with DERs and SAPs, and applicable DOT requirements.
4. An MRO receives a confirmed positive laboratory result. What is the most
appropriate initial approach?
A. Immediately report the employee as having refused the test
B. Automatically report the result as positive without contacting the employee
C. Follow the verification procedures required by Part 40
D. Ask the employer to determine whether the result is medically justified
Answer: C
Rationale: A confirmed laboratory result requiring MRO review must be handled
under the applicable verification procedures. The MRO's role is to independently
evaluate the result and, where required, give the employee an opportunity to
provide relevant medical information. The employer does not make the medical-
verification determination.
5. What is the MRO's fundamental professional posture when reviewing a
DOT drug test?
A. Advocate exclusively for the employer
B. Advocate exclusively for the employee
C. Remain independent and impartial
D. Defer all decisions to the laboratory
Answer: C
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Rationale: DOT specifically describes the MRO as an independent and
impartial “gatekeeper” who advocates for the accuracy and integrity of the
testing process.
6. A laboratory reports a specimen as adulterated. How should the MRO
initially treat that report?
A. Ignore the result because adulteration is not a drug result
B. Treat it using the applicable verification procedures for adulterated specimens
C. Automatically classify it as negative
D. Send the specimen directly to the employer without review
Answer: B
Rationale: Under §40.145, when the laboratory reports a specimen as adulterated
or substituted, the MRO treats the laboratory report in the same general manner as
a confirmed positive drug result, following the specified verification procedures
and explaining the laboratory findings to the employee during the verification
process.
7. A laboratory reports a specimen as substituted. Which statement is most
accurate?
A. The MRO must automatically classify it as negative
B. The MRO must handle it under the Part 40 verification process applicable to
substituted specimens
C. The employer alone decides whether substitution occurred
D. The MRO may disregard the laboratory's validity findings
Answer: B
Rationale: Substitution is a specimen-validity issue that requires MRO action
under §40.145 and the related Part 40 procedures. The MRO should explain the
laboratory findings and address relevant technical issues raised during verification.
8. A laboratory reports an invalid result. What is an important initial MRO
responsibility?
A. Automatically report the employee positive
B. Discuss the laboratory result with the certifying scientist as required
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C. Destroy the original chain-of-custody documentation
D. Ask the employer to reinterpret the laboratory result
Answer: B
Rationale: Under §40.159, when a laboratory reports an invalid result, the MRO
must discuss the result with the certifying scientist to determine whether additional
testing is necessary. The MRO then follows the prescribed procedures for
contacting and evaluating the employee.
9. During review of an invalid result, what medical information should the
MRO inquire about?
A. Only the employee's employment history
B. Medications and other information potentially relevant to the invalid result
C. The employee's annual salary
D. The employer's disciplinary policy
Answer: B
Rationale: The MRO must determine whether the employee has a medical
explanation for the invalid result and is required to inquire about medications the
employee may have taken.
10. A negative laboratory result is best described as:
A. A specimen containing a drug at any detectable concentration
B. A valid specimen in which no drug is present or the concentration is below the
applicable cutoff
C. A specimen that was not received by the laboratory
D. A specimen that was reported as substituted
Answer: B
Rationale: Part 40 defines a negative result as one reported by an HHS-certified
laboratory when the specimen contains no drug or the concentration is below the
applicable cutoff, provided the specimen is valid.
11. Why is chain of custody important in the DOT drug-testing process?
MEDICAL REVIEW OFFICER (MRO) ACTUAL EXAM
2026/2027 ACCURATE TEST COMPLETE ACTUAL
QUESTIONS AND CORRECT ANSWERS WITH DETAILED
RATIONALES (100% CORRECT VERIFIED SOLUTIONS)
LATEST UPDATED VERSION 2026
1. Which statement best describes the primary role of a Medical Review
Officer (MRO) in the DOT drug-testing program?
A. To determine whether an employer should terminate an employee after a
positive test
B. To independently review laboratory results and evaluate legitimate medical
explanations for certain results
C. To collect every specimen submitted for DOT testing
D. To provide substance-abuse treatment to employees who test positive
Answer: B
Rationale: The MRO serves as an independent and impartial gatekeeper for the
drug-testing process. The MRO reviews laboratory results and evaluates whether a
legitimate medical explanation exists for certain confirmed results. The MRO does
not make employment decisions or function as the employee's treatment provider
merely by serving as MRO.
2. Which professional may qualify as a DOT MRO?
A. Any licensed registered nurse
B. Any pharmacist with toxicology experience
C. A licensed physician who satisfies the applicable qualification and training
requirements
D. Any physician assistant who completes a drug-testing course
Answer: C
Rationale: Under §40.121, an MRO must be a licensed physician—Doctor of
Medicine or Osteopathy—and must satisfy the specified knowledge and
qualification-training requirements.
,2|Page
3. Which topic is specifically part of the required MRO qualification training?
A. Employee payroll administration
B. Specimen collection procedures
C. Workers' compensation litigation
D. Employer hiring practices
Answer: B
Rationale: MRO qualification training must cover areas including specimen
collection procedures, chain of custody, reporting and recordkeeping,
interpretation of drug and validity-test results, MRO responsibilities,
interaction with DERs and SAPs, and applicable DOT requirements.
4. An MRO receives a confirmed positive laboratory result. What is the most
appropriate initial approach?
A. Immediately report the employee as having refused the test
B. Automatically report the result as positive without contacting the employee
C. Follow the verification procedures required by Part 40
D. Ask the employer to determine whether the result is medically justified
Answer: C
Rationale: A confirmed laboratory result requiring MRO review must be handled
under the applicable verification procedures. The MRO's role is to independently
evaluate the result and, where required, give the employee an opportunity to
provide relevant medical information. The employer does not make the medical-
verification determination.
5. What is the MRO's fundamental professional posture when reviewing a
DOT drug test?
A. Advocate exclusively for the employer
B. Advocate exclusively for the employee
C. Remain independent and impartial
D. Defer all decisions to the laboratory
Answer: C
,3|Page
Rationale: DOT specifically describes the MRO as an independent and
impartial “gatekeeper” who advocates for the accuracy and integrity of the
testing process.
6. A laboratory reports a specimen as adulterated. How should the MRO
initially treat that report?
A. Ignore the result because adulteration is not a drug result
B. Treat it using the applicable verification procedures for adulterated specimens
C. Automatically classify it as negative
D. Send the specimen directly to the employer without review
Answer: B
Rationale: Under §40.145, when the laboratory reports a specimen as adulterated
or substituted, the MRO treats the laboratory report in the same general manner as
a confirmed positive drug result, following the specified verification procedures
and explaining the laboratory findings to the employee during the verification
process.
7. A laboratory reports a specimen as substituted. Which statement is most
accurate?
A. The MRO must automatically classify it as negative
B. The MRO must handle it under the Part 40 verification process applicable to
substituted specimens
C. The employer alone decides whether substitution occurred
D. The MRO may disregard the laboratory's validity findings
Answer: B
Rationale: Substitution is a specimen-validity issue that requires MRO action
under §40.145 and the related Part 40 procedures. The MRO should explain the
laboratory findings and address relevant technical issues raised during verification.
8. A laboratory reports an invalid result. What is an important initial MRO
responsibility?
A. Automatically report the employee positive
B. Discuss the laboratory result with the certifying scientist as required
, 4|Page
C. Destroy the original chain-of-custody documentation
D. Ask the employer to reinterpret the laboratory result
Answer: B
Rationale: Under §40.159, when a laboratory reports an invalid result, the MRO
must discuss the result with the certifying scientist to determine whether additional
testing is necessary. The MRO then follows the prescribed procedures for
contacting and evaluating the employee.
9. During review of an invalid result, what medical information should the
MRO inquire about?
A. Only the employee's employment history
B. Medications and other information potentially relevant to the invalid result
C. The employee's annual salary
D. The employer's disciplinary policy
Answer: B
Rationale: The MRO must determine whether the employee has a medical
explanation for the invalid result and is required to inquire about medications the
employee may have taken.
10. A negative laboratory result is best described as:
A. A specimen containing a drug at any detectable concentration
B. A valid specimen in which no drug is present or the concentration is below the
applicable cutoff
C. A specimen that was not received by the laboratory
D. A specimen that was reported as substituted
Answer: B
Rationale: Part 40 defines a negative result as one reported by an HHS-certified
laboratory when the specimen contains no drug or the concentration is below the
applicable cutoff, provided the specimen is valid.
11. Why is chain of custody important in the DOT drug-testing process?
