Medical Review Officer (MRO) Certification Exam
2026–2027
Occupational Health and Drug Testing
150 Practice Questions with Rationales
SECTION 1: MRO ROLE & RESPONSIBILITIES (Questions 1-25)
1. What is the primary responsibility of a Medical Review Officer (MRO) in
workplace drug testing?
A. Collecting urine samples from employees
B. Conducting initial immunoassay screenings
C. Reviewing and validating laboratory drug test results before they become final
D. Implementing workplace drug testing policies
Answer: C
Rationale: The MRO is a licensed physician trained to review and validate laboratory drug
test results. Their primary role is to ensure accuracy and legal defensibility by evaluating
the testing process and considering legitimate medical explanations for positive results
before final reporting .
2. Which of the following is a critical function of the MRO in the drug testing
process?
A. Determining which employees to test
B. Ensuring the testing process is legally defensible
,C. Setting cutoff levels for drug testing
D. Conducting random selection of employees
Answer: B
Rationale: The MRO must ensure that the testing process is quality-assured, traceable from
sampling to reporting, and legally defensible. This includes evaluating the risk of sample
adulteration and ensuring proper chain of custody .
3. Before a positive drug test result becomes final, the MRO must:
A. Immediately report it to the employer
B. Provide the donor an opportunity to discuss the outcome
C. Require the donor to take another test
D. Notify the employee's supervisor
Answer: B
Rationale: Before a drug-positive test result is finalized and communicated, the individual
must be provided an opportunity to discuss the outcome and present any prescription
medications or other medical explanations .
4. An MRO may change a positive test result to "verified negative" if:
A. The donor refuses to discuss the result
B. The donor can provide evidence of a valid prescription
C. The donor claims they did not use the substance
D. The employer requests a negative result
Answer: B
Rationale: If the MRO concludes that the substance use is legitimate (e.g., prescribed
medication with proper documentation), the test result is changed to "verified negative"
and reported to the employer as such .
,5. Which of the following substances most commonly requires MRO verification
due to legitimate medical use?
A. Cannabis
B. Cocaine
C. Opiates
D. Methamphetamine
Answer: C
Rationale: In workplace drug testing studies, 71% of samples containing opiates were
MRO-verified to be due to medical prescription. Similarly, 63% of amphetamine-positive
samples and 44% of benzodiazepine-positive samples were due to prescription use .
6. What percentage of opiate-positive workplace drug tests were found to be due
to medical prescription after MRO review?
A. 44%
B. 63%
C. 71%
D. 90%
Answer: C
Rationale: Research has shown that 71% of workplace drug test samples containing
opiates were verified by an MRO to be due to medical prescription rather than illicit use .
7. The MRO should verify that the testing process includes which of the following?
A. Only immunochemical screening
B. Confirmation by mass spectrometry for all non-negative results
C. Only visual inspection of samples
D. One-step testing without confirmation
Answer: B
Rationale: All preliminary positive results must be confirmed by liquid chromatography–
tandem mass spectrometry (LC–MS/MS) on a new subsample. Only MS/MS-confirmed
positive test results should be reported .
, 8. An MRO should be certified and trained in which areas?
A. Only laboratory analysis
B. Review and validation of drug test results
C. Only DOT regulations
D. Only specimen collection
Answer: B
Rationale: The MRO is a specialist-trained physician certified to review and validate
laboratory results. This includes ensuring quality assurance, traceable chain of custody,
proper interpretation, and legal defensibility .
9. What is the MRO's role regarding confidentiality of drug test results?
A. Results can be shared with anyone upon request
B. The MRO must be cognizant of confidentiality and consent when dealing with third
parties
C. Confidentiality is not required in occupational testing
D. Results are public record
Answer: B
Rationale: The MRO must maintain confidentiality and respect donor consent when
communicating with third parties such as employers and laboratories. Drug test results are
considered sensitive personal data .
10. Which of the following would require MRO review before a final result is
reported?
A. A negative screening result
B. A non-negative result requiring laboratory confirmation
C. A sample with normal creatinine levels
D. A sample collected without incident
Answer: B
2026–2027
Occupational Health and Drug Testing
150 Practice Questions with Rationales
SECTION 1: MRO ROLE & RESPONSIBILITIES (Questions 1-25)
1. What is the primary responsibility of a Medical Review Officer (MRO) in
workplace drug testing?
A. Collecting urine samples from employees
B. Conducting initial immunoassay screenings
C. Reviewing and validating laboratory drug test results before they become final
D. Implementing workplace drug testing policies
Answer: C
Rationale: The MRO is a licensed physician trained to review and validate laboratory drug
test results. Their primary role is to ensure accuracy and legal defensibility by evaluating
the testing process and considering legitimate medical explanations for positive results
before final reporting .
2. Which of the following is a critical function of the MRO in the drug testing
process?
A. Determining which employees to test
B. Ensuring the testing process is legally defensible
,C. Setting cutoff levels for drug testing
D. Conducting random selection of employees
Answer: B
Rationale: The MRO must ensure that the testing process is quality-assured, traceable from
sampling to reporting, and legally defensible. This includes evaluating the risk of sample
adulteration and ensuring proper chain of custody .
3. Before a positive drug test result becomes final, the MRO must:
A. Immediately report it to the employer
B. Provide the donor an opportunity to discuss the outcome
C. Require the donor to take another test
D. Notify the employee's supervisor
Answer: B
Rationale: Before a drug-positive test result is finalized and communicated, the individual
must be provided an opportunity to discuss the outcome and present any prescription
medications or other medical explanations .
4. An MRO may change a positive test result to "verified negative" if:
A. The donor refuses to discuss the result
B. The donor can provide evidence of a valid prescription
C. The donor claims they did not use the substance
D. The employer requests a negative result
Answer: B
Rationale: If the MRO concludes that the substance use is legitimate (e.g., prescribed
medication with proper documentation), the test result is changed to "verified negative"
and reported to the employer as such .
,5. Which of the following substances most commonly requires MRO verification
due to legitimate medical use?
A. Cannabis
B. Cocaine
C. Opiates
D. Methamphetamine
Answer: C
Rationale: In workplace drug testing studies, 71% of samples containing opiates were
MRO-verified to be due to medical prescription. Similarly, 63% of amphetamine-positive
samples and 44% of benzodiazepine-positive samples were due to prescription use .
6. What percentage of opiate-positive workplace drug tests were found to be due
to medical prescription after MRO review?
A. 44%
B. 63%
C. 71%
D. 90%
Answer: C
Rationale: Research has shown that 71% of workplace drug test samples containing
opiates were verified by an MRO to be due to medical prescription rather than illicit use .
7. The MRO should verify that the testing process includes which of the following?
A. Only immunochemical screening
B. Confirmation by mass spectrometry for all non-negative results
C. Only visual inspection of samples
D. One-step testing without confirmation
Answer: B
Rationale: All preliminary positive results must be confirmed by liquid chromatography–
tandem mass spectrometry (LC–MS/MS) on a new subsample. Only MS/MS-confirmed
positive test results should be reported .
, 8. An MRO should be certified and trained in which areas?
A. Only laboratory analysis
B. Review and validation of drug test results
C. Only DOT regulations
D. Only specimen collection
Answer: B
Rationale: The MRO is a specialist-trained physician certified to review and validate
laboratory results. This includes ensuring quality assurance, traceable chain of custody,
proper interpretation, and legal defensibility .
9. What is the MRO's role regarding confidentiality of drug test results?
A. Results can be shared with anyone upon request
B. The MRO must be cognizant of confidentiality and consent when dealing with third
parties
C. Confidentiality is not required in occupational testing
D. Results are public record
Answer: B
Rationale: The MRO must maintain confidentiality and respect donor consent when
communicating with third parties such as employers and laboratories. Drug test results are
considered sensitive personal data .
10. Which of the following would require MRO review before a final result is
reported?
A. A negative screening result
B. A non-negative result requiring laboratory confirmation
C. A sample with normal creatinine levels
D. A sample collected without incident
Answer: B
