MRO Practice Exam 2026/2027 | 100 Verified Questions with Complete Solutions
MRO Practice Exam 2026/2027
100 Verified Questions with Complete Solutions | Graded A+
Medical Review Officer (MRO) Certification and Practice Examination Preparation - aligned with current DOT (49 CFR Part
40) and non-DOT drug testing regulations, HHS Mandatory Guidelines, and MRO practice standards established by AAMRO
and ACOEM. Latest 2026/2027 update.
Solutions: Answer +
Format: Multiple Choice
Total Questions: 100 Sections: 10 detailed MRO rationale per
(A-D), one correct
question
Section 1: Regulatory Framework and Legal Considerations (Q1-Q15)
DOT vs. Non-DOT Regulations, 49 CFR Part 40, State Laws, and Chain of Custody
Q1: A CDL driver working for a FMCSA-regulated motor carrier produces a urine specimen that confirms
positive for marijuana metabolite (THCA) at 42 ng/mL. During the MRO verification interview, the driver
presents a valid medical marijuana card issued by the state in which he works and states that his nightly
cannabis use is legal under that state's Compassionate Use Act. What is the MRO's correct verification
decision?
A. Verify the result as positive; marijuana remains a Schedule I substance under federal law, and state
medical marijuana authorization is never an accepted medical explanation for a DOT-regulated donor
[CORRECT]
B. Verify the result as negative because a valid state-issued medical marijuana card constitutes a
legitimate prescription
C. Cancel the test and refer the driver to the state medical board for review of his authorization
D. Verify the result as positive but instruct the employer to disregard it under the state Compassionate
Use Act
Correct Answer: A
Rationale: The DOT and 49 CFR Part 40 framework hold that marijuana remains a Schedule I controlled
substance under the federal Controlled Substances Act regardless of state legalization, and DOT has expressly
stated that state medical marijuana laws provide no legitimate medical explanation for safety-sensitive employees.
Option B incorrectly treats a state card as a prescription for federal testing purposes; there is no such thing as a
federal prescription for marijuana. Option C misapplies cancellation authority, which is reserved for procedural
defects in the collection or custody process, not for donor explanations. Option D improperly directs the employer
to ignore a verified result, which would itself violate the employer's obligations under Part 40 and Part 382.
Graded A+ | Verified Solutions | DOT 49 CFR Part 40 / HHS / AAMRO / ACOEM aligned 1
,MRO Practice Exam 2026/2027 | 100 Verified Questions with Complete Solutions
Q2: Under 49 CFR Part 40 and the HHS Mandatory Guidelines, which laboratory is authorized to analyze
urine specimens collected for a DOT-regulated drug test?
A. Any CLIA-waived physician office laboratory that can perform the five-panel screen
B. Any laboratory accredited by the College of American Pathologists regardless of federal status
C. Any laboratory operating under ISO/IEC 17025 accreditation
D. Only a laboratory currently certified by HHS under the Mandatory Guidelines and listed on
SAMHSA's certified facility list [CORRECT]
Correct Answer: D
Rationale: Part 40 requires that all DOT drug testing be performed at laboratories holding current HHS
certification under the Mandatory Guidelines for Federal Workplace Drug Testing Programs, administered by
SAMHSA through the National Laboratory Certification Program. CLIA waiver, CAP accreditation, and ISO
17025 accreditation (options A, B, and C) are laboratory quality frameworks, but none of them substitutes for
HHS certification for DOT purposes. Using any non-certified laboratory invalidates the test as a DOT test and
exposes the employer to serious compliance consequences.
Q3: Which change was made to the DOT 5-panel drug test by the final rule published in 2017 (effective
January 1, 2018)?
A. Fentanyl was added as a sixth analyte to the panel
B. Buprenorphine was added to replace methadone screening
C. Four semi-synthetic opioid analytes were added: hydrocodone, hydromorphone, oxycodone, and
oxymorphone [CORRECT]
D. Meperidine was added to the amphetamine confirmation panel
Correct Answer: C
Rationale: The 2017 DOT final rule aligned the DOT panel with the revised HHS Mandatory Guidelines by
adding the four semi-synthetic opioids - hydrocodone, hydromorphone, oxycodone, and oxymorphone - to the
pre-existing opiates (codeine, morphine, 6-AM). Fentanyl, buprenorphine, and meperidine were specifically
considered and not added to the DOT panel. Option D is doubly wrong because these synthetic and atypical
opioids are not confirmed within the amphetamine panel, which covers amphetamine, methamphetamine, and
MDMA/MDA.
Q4: A state enacts legislation legalizing recreational marijuana and prohibiting employers from
discriminating against off-duty users. An FMCSA-regulated carrier operates exclusively within that state.
Which statement correctly describes the interaction between state law and federal DOT testing authority?
A. State legalization supersedes DOT rules for drivers who operate only within the state
B. DOT regulations preempt inconsistent state law for federally regulated testing; employers and
MROs must apply Part 40 requirements regardless of state marijuana policy [CORRECT]
C. The MRO may apply state law whenever the collection physically occurred in the marijuana-legal
state
D. Federal preemption applies to DOT drug testing but never to DOT alcohol testing
Correct Answer: B
Rationale: DOT testing operates under the Supremacy Clause of the U.S. Constitution: Part 40 and agency rules
such as Part 382 occupy the field for federally regulated safety-sensitive testing, and states cannot authorize what
federal law prohibits. Option A states the reverse of the actual preemption doctrine. Option C is wrong because
neither the collection site's location nor the donor's residence changes the applicable federal standard. Option D is
wrong because DOT alcohol testing rules (Part 40 Subparts J through M) are preempted against inconsistent state
schemes in the same way as the drug testing rules.
Graded A+ | Verified Solutions | DOT 49 CFR Part 40 / HHS / AAMRO / ACOEM aligned 2
,MRO Practice Exam 2026/2027 | 100 Verified Questions with Complete Solutions
Q5: Under the Drug-Free Workplace Act of 1988, what is required of federal contractors and grantees that
are covered by the Act?
A. Mandatory random drug testing of every employee on the contract
B. Establishment of a written drug-free workplace policy and an ongoing drug-free awareness program,
without any federal mandate to conduct testing [CORRECT]
C. MRO review of all laboratory results generated under the contract
D. Annual renewal of HHS certification for any laboratory used by the contractor
Correct Answer: B
Rationale: The Drug-Free Workplace Act of 1988 requires covered federal contractors and grantees to certify
that they maintain a drug-free workplace, which entails publishing a written policy, establishing a drug-free
awareness program, and taking personnel actions for workplace violations. The Act famously does not itself
mandate drug testing; testing programs arise from other authorities such as DOT rules, the HHS Mandatory
Guidelines for federal executive branch employees, or state law. Options A, C, and D describe requirements that
belong to other regimes and do not appear in the Act.
Q6: During a DOT collection, the collector notices she recorded the wrong collection date in Step 1 of the
Federal Custody and Control Form (CCF). She draws a single line through the incorrect date, writes the
correct date beside it, and initials and dates the correction. How should this correction be handled?
A. The correction is acceptable under Part 40, which permits corrections made by a single line through
the error with the collector's initial and date [CORRECT]
B. The CCF is fatally flawed and the specimen must be recollected immediately
C. The correction is valid only if the laboratory director reviews and approves it in writing
D. The correction is invalid unless the MRO re-interviews the donor and documents the correct date
Correct Answer: A
Rationale: Part 40 collection procedures expressly allow collectors to correct clerical errors on the CCF by
crossing out the incorrect information with a single line, entering the correct information, and initialing and dating
the change; correction fluid is prohibited precisely because the original entry must remain legible. Option B
incorrectly declares a routine permissible correction to be a fatal flaw; fatal flaws are uncorrected problems such
as missing donor identifiers or missing collector certification. Options C and D invent approval steps that do not
exist in the rule; neither the laboratory director nor a re-interview is required to legitimize a properly made
correction.
Graded A+ | Verified Solutions | DOT 49 CFR Part 40 / HHS / AAMRO / ACOEM aligned 3
, MRO Practice Exam 2026/2027 | 100 Verified Questions with Complete Solutions
Q7: Which statement best describes the independence requirements that govern the Medical Review Officer
in a DOT drug testing program?
A. The MRO may be a part-time employee of the HHS-certified laboratory as long as the laboratory
does not influence verification decisions
B. The MRO may be employed by the testing laboratory if the Designated Employer Representative
signs a conflict waiver
C. The MRO may review the positive result of a family member if another physician co-signs the
verification decision
D. The MRO must not be an employee of or under the control of the HHS-certified laboratory, and
must not review the results of family members or the MRO's own test results [CORRECT]
Correct Answer: D
Rationale: Part 40 (Subpart G) requires the MRO to be an independent, licensed physician free of conflicts: the
MRO may not be employed by, receive compensation from, or be under the control of the testing laboratory, and
may not review results in which the MRO has a personal stake, including the results of family members or the
MRO's own specimens. Options A and B describe prohibited employment relationships regardless of claimed
safeguards or waivers. Option C fails because a co-signature cannot cure a direct personal conflict; the employer
must arrange an alternate MRO for such cases.
Q8: Which federal department issues the Mandatory Guidelines for Federal Workplace Drug Testing
Programs that govern certified laboratories and federal agency testing programs?
A. The Department of Transportation
B. The Drug Enforcement Administration
C. The Department of Health and Human Services [CORRECT]
D. The Office of Personnel Management
Correct Answer: C
Rationale: The Mandatory Guidelines are issued and periodically revised by the Secretary of Health and Human
Services under authority of Public Law 100-690, with SAMHSA administering the certification program and the
National Laboratory Certification Program inspecting and accrediting laboratories. DOT adopts the HHS
framework by reference in Part 40 but does not itself issue the Guidelines. The DEA enforces the Controlled
Substances Act and schedules drugs, and OPM oversees federal employment policy; neither issues laboratory
certification standards.
Q9: A small motor carrier sends its DOT-regulated urine specimens to a convenient local hospital laboratory
that is not HHS-certified, and the MRO verifies the results. What is the consequence of this practice?
A. The test is not a valid DOT test; results from a non-certified laboratory cannot be used for Part 40
purposes, and the carrier faces DOT non-compliance exposure [CORRECT]
B. The results are acceptable as long as all positives were confirmed by GC-MS
C. The results are acceptable if the MRO verifies them within 24 hours of receipt
D. The results are valid if each donor signed a consent acknowledging the non-certified laboratory
Correct Answer: A
Rationale: Part 40 makes HHS certification of the testing laboratory a jurisdictional prerequisite for a valid DOT
test; analysis anywhere else produces a result with no DOT force, no matter how sophisticated the instrumentation
or how prompt the MRO review. Options B, C, and D all purport to validate an inherently non-conforming test,
but neither confirmation testing, MRO timing, nor donor consent can substitute for certification. The carrier must
use an HHS-certified laboratory and could face enforcement action, including against service agents, for repeated
violations.
Graded A+ | Verified Solutions | DOT 49 CFR Part 40 / HHS / AAMRO / ACOEM aligned 4
MRO Practice Exam 2026/2027
100 Verified Questions with Complete Solutions | Graded A+
Medical Review Officer (MRO) Certification and Practice Examination Preparation - aligned with current DOT (49 CFR Part
40) and non-DOT drug testing regulations, HHS Mandatory Guidelines, and MRO practice standards established by AAMRO
and ACOEM. Latest 2026/2027 update.
Solutions: Answer +
Format: Multiple Choice
Total Questions: 100 Sections: 10 detailed MRO rationale per
(A-D), one correct
question
Section 1: Regulatory Framework and Legal Considerations (Q1-Q15)
DOT vs. Non-DOT Regulations, 49 CFR Part 40, State Laws, and Chain of Custody
Q1: A CDL driver working for a FMCSA-regulated motor carrier produces a urine specimen that confirms
positive for marijuana metabolite (THCA) at 42 ng/mL. During the MRO verification interview, the driver
presents a valid medical marijuana card issued by the state in which he works and states that his nightly
cannabis use is legal under that state's Compassionate Use Act. What is the MRO's correct verification
decision?
A. Verify the result as positive; marijuana remains a Schedule I substance under federal law, and state
medical marijuana authorization is never an accepted medical explanation for a DOT-regulated donor
[CORRECT]
B. Verify the result as negative because a valid state-issued medical marijuana card constitutes a
legitimate prescription
C. Cancel the test and refer the driver to the state medical board for review of his authorization
D. Verify the result as positive but instruct the employer to disregard it under the state Compassionate
Use Act
Correct Answer: A
Rationale: The DOT and 49 CFR Part 40 framework hold that marijuana remains a Schedule I controlled
substance under the federal Controlled Substances Act regardless of state legalization, and DOT has expressly
stated that state medical marijuana laws provide no legitimate medical explanation for safety-sensitive employees.
Option B incorrectly treats a state card as a prescription for federal testing purposes; there is no such thing as a
federal prescription for marijuana. Option C misapplies cancellation authority, which is reserved for procedural
defects in the collection or custody process, not for donor explanations. Option D improperly directs the employer
to ignore a verified result, which would itself violate the employer's obligations under Part 40 and Part 382.
Graded A+ | Verified Solutions | DOT 49 CFR Part 40 / HHS / AAMRO / ACOEM aligned 1
,MRO Practice Exam 2026/2027 | 100 Verified Questions with Complete Solutions
Q2: Under 49 CFR Part 40 and the HHS Mandatory Guidelines, which laboratory is authorized to analyze
urine specimens collected for a DOT-regulated drug test?
A. Any CLIA-waived physician office laboratory that can perform the five-panel screen
B. Any laboratory accredited by the College of American Pathologists regardless of federal status
C. Any laboratory operating under ISO/IEC 17025 accreditation
D. Only a laboratory currently certified by HHS under the Mandatory Guidelines and listed on
SAMHSA's certified facility list [CORRECT]
Correct Answer: D
Rationale: Part 40 requires that all DOT drug testing be performed at laboratories holding current HHS
certification under the Mandatory Guidelines for Federal Workplace Drug Testing Programs, administered by
SAMHSA through the National Laboratory Certification Program. CLIA waiver, CAP accreditation, and ISO
17025 accreditation (options A, B, and C) are laboratory quality frameworks, but none of them substitutes for
HHS certification for DOT purposes. Using any non-certified laboratory invalidates the test as a DOT test and
exposes the employer to serious compliance consequences.
Q3: Which change was made to the DOT 5-panel drug test by the final rule published in 2017 (effective
January 1, 2018)?
A. Fentanyl was added as a sixth analyte to the panel
B. Buprenorphine was added to replace methadone screening
C. Four semi-synthetic opioid analytes were added: hydrocodone, hydromorphone, oxycodone, and
oxymorphone [CORRECT]
D. Meperidine was added to the amphetamine confirmation panel
Correct Answer: C
Rationale: The 2017 DOT final rule aligned the DOT panel with the revised HHS Mandatory Guidelines by
adding the four semi-synthetic opioids - hydrocodone, hydromorphone, oxycodone, and oxymorphone - to the
pre-existing opiates (codeine, morphine, 6-AM). Fentanyl, buprenorphine, and meperidine were specifically
considered and not added to the DOT panel. Option D is doubly wrong because these synthetic and atypical
opioids are not confirmed within the amphetamine panel, which covers amphetamine, methamphetamine, and
MDMA/MDA.
Q4: A state enacts legislation legalizing recreational marijuana and prohibiting employers from
discriminating against off-duty users. An FMCSA-regulated carrier operates exclusively within that state.
Which statement correctly describes the interaction between state law and federal DOT testing authority?
A. State legalization supersedes DOT rules for drivers who operate only within the state
B. DOT regulations preempt inconsistent state law for federally regulated testing; employers and
MROs must apply Part 40 requirements regardless of state marijuana policy [CORRECT]
C. The MRO may apply state law whenever the collection physically occurred in the marijuana-legal
state
D. Federal preemption applies to DOT drug testing but never to DOT alcohol testing
Correct Answer: B
Rationale: DOT testing operates under the Supremacy Clause of the U.S. Constitution: Part 40 and agency rules
such as Part 382 occupy the field for federally regulated safety-sensitive testing, and states cannot authorize what
federal law prohibits. Option A states the reverse of the actual preemption doctrine. Option C is wrong because
neither the collection site's location nor the donor's residence changes the applicable federal standard. Option D is
wrong because DOT alcohol testing rules (Part 40 Subparts J through M) are preempted against inconsistent state
schemes in the same way as the drug testing rules.
Graded A+ | Verified Solutions | DOT 49 CFR Part 40 / HHS / AAMRO / ACOEM aligned 2
,MRO Practice Exam 2026/2027 | 100 Verified Questions with Complete Solutions
Q5: Under the Drug-Free Workplace Act of 1988, what is required of federal contractors and grantees that
are covered by the Act?
A. Mandatory random drug testing of every employee on the contract
B. Establishment of a written drug-free workplace policy and an ongoing drug-free awareness program,
without any federal mandate to conduct testing [CORRECT]
C. MRO review of all laboratory results generated under the contract
D. Annual renewal of HHS certification for any laboratory used by the contractor
Correct Answer: B
Rationale: The Drug-Free Workplace Act of 1988 requires covered federal contractors and grantees to certify
that they maintain a drug-free workplace, which entails publishing a written policy, establishing a drug-free
awareness program, and taking personnel actions for workplace violations. The Act famously does not itself
mandate drug testing; testing programs arise from other authorities such as DOT rules, the HHS Mandatory
Guidelines for federal executive branch employees, or state law. Options A, C, and D describe requirements that
belong to other regimes and do not appear in the Act.
Q6: During a DOT collection, the collector notices she recorded the wrong collection date in Step 1 of the
Federal Custody and Control Form (CCF). She draws a single line through the incorrect date, writes the
correct date beside it, and initials and dates the correction. How should this correction be handled?
A. The correction is acceptable under Part 40, which permits corrections made by a single line through
the error with the collector's initial and date [CORRECT]
B. The CCF is fatally flawed and the specimen must be recollected immediately
C. The correction is valid only if the laboratory director reviews and approves it in writing
D. The correction is invalid unless the MRO re-interviews the donor and documents the correct date
Correct Answer: A
Rationale: Part 40 collection procedures expressly allow collectors to correct clerical errors on the CCF by
crossing out the incorrect information with a single line, entering the correct information, and initialing and dating
the change; correction fluid is prohibited precisely because the original entry must remain legible. Option B
incorrectly declares a routine permissible correction to be a fatal flaw; fatal flaws are uncorrected problems such
as missing donor identifiers or missing collector certification. Options C and D invent approval steps that do not
exist in the rule; neither the laboratory director nor a re-interview is required to legitimize a properly made
correction.
Graded A+ | Verified Solutions | DOT 49 CFR Part 40 / HHS / AAMRO / ACOEM aligned 3
, MRO Practice Exam 2026/2027 | 100 Verified Questions with Complete Solutions
Q7: Which statement best describes the independence requirements that govern the Medical Review Officer
in a DOT drug testing program?
A. The MRO may be a part-time employee of the HHS-certified laboratory as long as the laboratory
does not influence verification decisions
B. The MRO may be employed by the testing laboratory if the Designated Employer Representative
signs a conflict waiver
C. The MRO may review the positive result of a family member if another physician co-signs the
verification decision
D. The MRO must not be an employee of or under the control of the HHS-certified laboratory, and
must not review the results of family members or the MRO's own test results [CORRECT]
Correct Answer: D
Rationale: Part 40 (Subpart G) requires the MRO to be an independent, licensed physician free of conflicts: the
MRO may not be employed by, receive compensation from, or be under the control of the testing laboratory, and
may not review results in which the MRO has a personal stake, including the results of family members or the
MRO's own specimens. Options A and B describe prohibited employment relationships regardless of claimed
safeguards or waivers. Option C fails because a co-signature cannot cure a direct personal conflict; the employer
must arrange an alternate MRO for such cases.
Q8: Which federal department issues the Mandatory Guidelines for Federal Workplace Drug Testing
Programs that govern certified laboratories and federal agency testing programs?
A. The Department of Transportation
B. The Drug Enforcement Administration
C. The Department of Health and Human Services [CORRECT]
D. The Office of Personnel Management
Correct Answer: C
Rationale: The Mandatory Guidelines are issued and periodically revised by the Secretary of Health and Human
Services under authority of Public Law 100-690, with SAMHSA administering the certification program and the
National Laboratory Certification Program inspecting and accrediting laboratories. DOT adopts the HHS
framework by reference in Part 40 but does not itself issue the Guidelines. The DEA enforces the Controlled
Substances Act and schedules drugs, and OPM oversees federal employment policy; neither issues laboratory
certification standards.
Q9: A small motor carrier sends its DOT-regulated urine specimens to a convenient local hospital laboratory
that is not HHS-certified, and the MRO verifies the results. What is the consequence of this practice?
A. The test is not a valid DOT test; results from a non-certified laboratory cannot be used for Part 40
purposes, and the carrier faces DOT non-compliance exposure [CORRECT]
B. The results are acceptable as long as all positives were confirmed by GC-MS
C. The results are acceptable if the MRO verifies them within 24 hours of receipt
D. The results are valid if each donor signed a consent acknowledging the non-certified laboratory
Correct Answer: A
Rationale: Part 40 makes HHS certification of the testing laboratory a jurisdictional prerequisite for a valid DOT
test; analysis anywhere else produces a result with no DOT force, no matter how sophisticated the instrumentation
or how prompt the MRO review. Options B, C, and D all purport to validate an inherently non-conforming test,
but neither confirmation testing, MRO timing, nor donor consent can substitute for certification. The carrier must
use an HHS-certified laboratory and could face enforcement action, including against service agents, for repeated
violations.
Graded A+ | Verified Solutions | DOT 49 CFR Part 40 / HHS / AAMRO / ACOEM aligned 4
