MRO PRACTICE EXAM Actual Exam 2026/2027 –
Complete Exam-Style Questions | 100% Verified
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EXAM QUESTIONS
SCENARIO 1: Positive Drug Test Result
SCENARIO: A 42-year-old male commercial truck driver (CDL holder) working for a DOT-
regulated motor carrier was randomly selected for a DOT drug test. The urine specimen was
collected under direct observation. Laboratory results show: Marijuana metabolite (THC) at 52
ng/mL in the initial screening, confirmed at 18 ng/mL by GC/MS. The donor has no prior
positive tests. He is taking no medications and reports no medical conditions. His urine specific
gravity is 1.003 and creatinine is 22 mg/dL.
Q1: What is the correct MRO verification decision for this result?
A. Negative - result
B. Positive - result
C. Refusal to test - substituted specimen
D. Refusal to test - dilute specimen
Correct Answer: A
Rationale: According to 49 CFR Part 40.137 and HHS Mandatory Guidelines, a confirmed THC
result of 15 ng/mL or above is required for a positive DOT test. The 18 ng/mL confirmation
exceeds the 15 ng/mL cutoff, resulting in a verified positive. The dilute specimen observation
(specific gravity 1.003, creatinine 22 mg/dL) does not change the positive result; it must still be
reported as positive under DOT rules.
Q2: The donor claims his THC-positive result is from using CBD products. What is the proper
MRO response?
A. Accept the CBD explanation and verify the test negative
B. Report the test as positive and inform the employer
C. Tell the donor to provide documentation of CBD product use
D. Dismiss the claim and verify the test positive without further inquiry
Correct Answer: C
Rationale: Under 49 CFR Part 40.135, the MRO must conduct a verification interview and review
any medical explanation. CBD products may contain trace THC, but the MRO should request
,documentation (product labels, certificates of analysis) and determine if the amount claimed
could produce a 52/18 ng/mL result. If the donor cannot provide adequate documentation, the
MRO must verify the result as positive.
Q3: The donor now admits he used marijuana 5 days ago at a party. He claims it was a one-
time use. What should the MRO verify?
A. Negative - one-time use doesn't warrant a positive
B. Positive - DOT regulations prohibit marijuana use regardless of frequency
C. Refusal to test - donor admitted to illicit drug use
D. Report to employer and recommend SAP evaluation
Correct Answer: B
Rationale: Under 49 CFR Part 40.137 and DOT drug testing rules, any confirmed marijuana
metabolite at or above the cutoff level (15 ng/mL) must be verified positive. The MRO has no
discretion to ignore a positive result based on frequency of use. The result must be reported to
the employer as a verified positive.
Q4: After verifying the positive result, what is the MRO's next required action?
A. Inform the donor he can continue working pending appeal
B. Report the verified positive result to the employer
C. Destroy the split specimen
D. Notify the donor's primary care physician
Correct Answer: B
Rationale: Per 49 CFR Part 40.135(a)(3) and .147, after completing the verification process, the
MRO must promptly report the verified positive result to the employer's designated employer
representative (DER). The MRO must maintain confidentiality and cannot discuss results with
anyone other than the employer's authorized representative.
Q5: The donor requests to have the split specimen tested. When must this request be made?
A. Within 72 hours of the positive result notification
B. Within 24 hours of the positive result notification
C. Within 7 days of the positive result notification
D. At any time before the employer takes adverse action
Correct Answer: A
Rationale: Under 49 CFR Part 40.187(b)(1), the donor has 72 hours from the time of receiving
the verified positive result notification to request the split specimen test. The MRO must
, document this timeframe and provide clear instructions on how the donor can initiate the split
specimen testing process through the laboratory.
Q6: The donor fails to request a split specimen test within the required timeframe. What
happens?
A. The MRO automatically orders a split specimen test
B. The positive result stands and is reported to the employer
C. The result is changed to a refusal to test
D. The donor is given an additional 72 hours
Correct Answer: B
Rationale: According to 49 CFR Part 40.187(c), if the donor fails to make a timely request for
split specimen testing (within 72 hours), the MRO verifies the test as positive and reports it to
the employer. The MRO cannot extend this deadline except in extreme, documented
circumstances (e.g., hospitalization).
SCENARIO 2: Adulterated Specimen
SCENARIO: A 35-year-old female nurse working for a hospital with a drug-free workplace policy
is randomly selected. The urine specimen temperature is 99.2°F (within 4 minutes of collection).
Laboratory results show: pH 4.2, creatinine 15 mg/dL, specific gravity 1.002, nitrite
concentration 450 μg/mL. All drug screen results are negative.
Q7: How should the MRO classify this specimen?
A. Negative-dilute
B. Positive for nitrites
C. Refusal to test - adulterated
D. Invalid specimen
Correct Answer: C
Rationale: Under HHS Mandatory Guidelines and 49 CFR Part 40.97, a specimen is classified as
adulterated when nitrite concentration exceeds 200 μg/mL. This is considered an adulterated
specimen, which, under DOT rules, constitutes a refusal to test (49 CFR Part 40.159). The
abnormally low pH and creatinine further support adulteration.
Q8: The donor claims she has a urinary tract infection and uses Uristat (phenazopyridine) for
symptoms. What is the proper MRO action?
A. Accept the medical explanation and verify the test negative
Complete Exam-Style Questions | 100% Verified
– Pass Guaranteed – A+ Graded
EXAM QUESTIONS
SCENARIO 1: Positive Drug Test Result
SCENARIO: A 42-year-old male commercial truck driver (CDL holder) working for a DOT-
regulated motor carrier was randomly selected for a DOT drug test. The urine specimen was
collected under direct observation. Laboratory results show: Marijuana metabolite (THC) at 52
ng/mL in the initial screening, confirmed at 18 ng/mL by GC/MS. The donor has no prior
positive tests. He is taking no medications and reports no medical conditions. His urine specific
gravity is 1.003 and creatinine is 22 mg/dL.
Q1: What is the correct MRO verification decision for this result?
A. Negative - result
B. Positive - result
C. Refusal to test - substituted specimen
D. Refusal to test - dilute specimen
Correct Answer: A
Rationale: According to 49 CFR Part 40.137 and HHS Mandatory Guidelines, a confirmed THC
result of 15 ng/mL or above is required for a positive DOT test. The 18 ng/mL confirmation
exceeds the 15 ng/mL cutoff, resulting in a verified positive. The dilute specimen observation
(specific gravity 1.003, creatinine 22 mg/dL) does not change the positive result; it must still be
reported as positive under DOT rules.
Q2: The donor claims his THC-positive result is from using CBD products. What is the proper
MRO response?
A. Accept the CBD explanation and verify the test negative
B. Report the test as positive and inform the employer
C. Tell the donor to provide documentation of CBD product use
D. Dismiss the claim and verify the test positive without further inquiry
Correct Answer: C
Rationale: Under 49 CFR Part 40.135, the MRO must conduct a verification interview and review
any medical explanation. CBD products may contain trace THC, but the MRO should request
,documentation (product labels, certificates of analysis) and determine if the amount claimed
could produce a 52/18 ng/mL result. If the donor cannot provide adequate documentation, the
MRO must verify the result as positive.
Q3: The donor now admits he used marijuana 5 days ago at a party. He claims it was a one-
time use. What should the MRO verify?
A. Negative - one-time use doesn't warrant a positive
B. Positive - DOT regulations prohibit marijuana use regardless of frequency
C. Refusal to test - donor admitted to illicit drug use
D. Report to employer and recommend SAP evaluation
Correct Answer: B
Rationale: Under 49 CFR Part 40.137 and DOT drug testing rules, any confirmed marijuana
metabolite at or above the cutoff level (15 ng/mL) must be verified positive. The MRO has no
discretion to ignore a positive result based on frequency of use. The result must be reported to
the employer as a verified positive.
Q4: After verifying the positive result, what is the MRO's next required action?
A. Inform the donor he can continue working pending appeal
B. Report the verified positive result to the employer
C. Destroy the split specimen
D. Notify the donor's primary care physician
Correct Answer: B
Rationale: Per 49 CFR Part 40.135(a)(3) and .147, after completing the verification process, the
MRO must promptly report the verified positive result to the employer's designated employer
representative (DER). The MRO must maintain confidentiality and cannot discuss results with
anyone other than the employer's authorized representative.
Q5: The donor requests to have the split specimen tested. When must this request be made?
A. Within 72 hours of the positive result notification
B. Within 24 hours of the positive result notification
C. Within 7 days of the positive result notification
D. At any time before the employer takes adverse action
Correct Answer: A
Rationale: Under 49 CFR Part 40.187(b)(1), the donor has 72 hours from the time of receiving
the verified positive result notification to request the split specimen test. The MRO must
, document this timeframe and provide clear instructions on how the donor can initiate the split
specimen testing process through the laboratory.
Q6: The donor fails to request a split specimen test within the required timeframe. What
happens?
A. The MRO automatically orders a split specimen test
B. The positive result stands and is reported to the employer
C. The result is changed to a refusal to test
D. The donor is given an additional 72 hours
Correct Answer: B
Rationale: According to 49 CFR Part 40.187(c), if the donor fails to make a timely request for
split specimen testing (within 72 hours), the MRO verifies the test as positive and reports it to
the employer. The MRO cannot extend this deadline except in extreme, documented
circumstances (e.g., hospitalization).
SCENARIO 2: Adulterated Specimen
SCENARIO: A 35-year-old female nurse working for a hospital with a drug-free workplace policy
is randomly selected. The urine specimen temperature is 99.2°F (within 4 minutes of collection).
Laboratory results show: pH 4.2, creatinine 15 mg/dL, specific gravity 1.002, nitrite
concentration 450 μg/mL. All drug screen results are negative.
Q7: How should the MRO classify this specimen?
A. Negative-dilute
B. Positive for nitrites
C. Refusal to test - adulterated
D. Invalid specimen
Correct Answer: C
Rationale: Under HHS Mandatory Guidelines and 49 CFR Part 40.97, a specimen is classified as
adulterated when nitrite concentration exceeds 200 μg/mL. This is considered an adulterated
specimen, which, under DOT rules, constitutes a refusal to test (49 CFR Part 40.159). The
abnormally low pH and creatinine further support adulteration.
Q8: The donor claims she has a urinary tract infection and uses Uristat (phenazopyridine) for
symptoms. What is the proper MRO action?
A. Accept the medical explanation and verify the test negative
