MRO Drug Testing Procedures 3 — Questions and Answers
Question 1: What initial testing method is required for DOT federal workplace urine drug screening?
- Gas chromatography/mass spectrometry (GC-MS)
- Immunoassay (Correct answer)
- Liquid chromatography-tandem mass spectrometry (LC-MS/MS)
- Thin-layer chromatography
Correct answer: Immunoassay
Immunoassay is the required initial screening method for all federally mandated urine drug tests.
Question 2: Which method must be used to confirm a positive immunoassay result in a federal workplace drug test?
- Repeat immunoassay on the same aliquot
- GC-MS or LC-MS/MS (Correct answer)
- Enzyme-linked immunosorbent assay (ELISA)
- High-performance liquid chromatography (HPLC) alone
Correct answer: GC-MS or LC-MS/MS
GC-MS or LC-MS/MS provides the definitive structural identification required for a confirmed positive result.
Question 3: What is the DOT initial immunoassay cutoff concentration for marijuana metabolite (THC-COOH) in urine?
- 25 ng/mL
- 50 ng/mL (Correct answer)
- 100 ng/mL
- 15 ng/mL
Correct answer: 50 ng/mL
The federally mandated initial screening cutoff for marijuana metabolites is 50 ng/mL.
Question 4: What is the GC-MS/LC-MS/MS confirmatory cutoff for THC-COOH in federal workplace urine testing?
- 50 ng/mL
- 25 ng/mL
- 15 ng/mL (Correct answer)
- 100 ng/mL
Correct answer: 15 ng/mL
The confirmatory cutoff for THC-COOH is 15 ng/mL, which is lower than the initial screen to ensure the screen's positive result is valid.
Question 5: Which five drug classes make up the standard DOT federal workplace urine drug testing panel?
- Marijuana, cocaine, opiates, phencyclidine, and amphetamines (Correct answer)
- Marijuana, cocaine, benzodiazepines, opiates, and barbiturates
- Marijuana, cocaine, alcohol, opiates, and amphetamines
- Cocaine, opiates, phencyclidine, amphetamines, and MDMA
Correct answer: Marijuana, cocaine, opiates, phencyclidine, and amphetamines
The DOT 5-panel tests for marijuana metabolites, cocaine metabolites, opiates, phencyclidine (PCP), and amphetamines.
Question 6: Which opioids were added to the federal drug testing panel by the 2017 HHS Mandatory Guidelines?
- Heroin and MDMA
- Hydrocodone, oxycodone, hydromorphone, and oxymorphone (Correct answer)
- Benzodiazepines and synthetic cannabinoids
- Tramadol and buprenorphine
Correct answer: Hydrocodone, oxycodone, hydromorphone, and oxymorphone
The 2017 HHS Mandatory Guidelines expanded the opiate panel to include four semi-synthetic opioids commonly involved in prescription drug abuse.
Question 7: To whom must the certified HHS laboratory report all federal workplace drug test results?
- Directly to the employer only
- Only positive results to the MRO
- All results to the MRO on an approved report form (Correct answer)
- Directly to the donor and the employer simultaneously
Correct answer: All results to the MRO on an approved report form
The laboratory must report all results — positive, negative, substituted, adulterated, or invalid — to the MRO, never directly to the employer.
MRO Drug Testing Procedures 3
What initial testing method is required for DOT federal workplace urine drug screening?