Drug testing is a vital component of workplace safety, particularly in industries regulated by the Department of Transportation (DOT). This guide will serve as an overview of the DOT Drug Testing program and will provide valuable insights for both employers and employees.
Below are some of the jobs that are subject to DOT drug testing. However, this is not an exhaustive list:
DOT drug testing is mandated in these 6 situations:
There are a lot of drugs/substances out there that will get you high. However, DOT drug testing looks for these 5 specific drugs for current employees and new applicants:
DOT drug testing involves two stages once the specimen gets to the laboratory, an initial screen and a confirmation.
During the “initial screening”, all specimens are run through a chemistry analyzer which will flag if any specimen is at or above the initial screening concentrations set by DOT.
During “confirmation”, any specimens that flagged during the initial screening, will get run a second time in order to validate the first run.
For Marijuana, Cocaine and Amphetamines, the DOT uses a lower concentration as the threshold to confirm a positive, making it a more sensitive test. However, for Opiates and Phencyclidine (PCP), the cutoff concentration does not change between the initial screen and the confirmation run.
The cutoff levels for each drug are as follows:
Marijuana
Cocaine
Amphetamines
Opioids
Phencyclidine (PCP)
This is the golden question for many people. However, the answer will vary since each individual drug metabolizes differently.
Detection times will depend on the type of drug, frequency of use, body composition, individual metabolism and type of specimen used for testing.
Despite this variability, we can estimate a rough idea of detection windows for each drug. Since urine is the most commonly used specimen type for DOT testing, we will show those detection windows below:
Most of the drugs on this list are “water soluble“, so they will generally clear from the system in about a week max.
On the other hand, marijuana is “fat soluble“, meaning that the drug is stored in fat cells instead of clearing the body quickly. This increases the window of detection for marijuana, especially with obese people since they have more fat stores to utilize. People with higher fat content stand a greater chance of testing positive for a longer period of time than a person with less fat content, with all else being equal.
The timeframe for receiving DOT drug test results depends on the outcome of the test.
-If the results are negative they should be available within 24-48 hours.
-If the results are positive, it may take up to 3-5 business days due to additional time required for confirmation testing and MRO review.
When a DOT employee tests positive and they aren’t able to give the MRO a valid medical reason during their interview, several steps are taken:
-The employee is immediately removed from safety-sensitive duties.
-They must complete the return-to-duty process, which includes:
-The employee will undergo follow-up testing for a minimum of 12 months after returning to safety-sensitive duty. This can be extended to an additional 48 months if the employer chooses. During the first 12 months, employees will be subject to a minimum of 6 unannounced follow-up tests.
Direct observation is not standard practice for DOT drug testing. However, it is required in specific situations like:
In these cases, a same-gender observer will watch the urine stream leave the body and enter the collection container. This helps reduce the chances of the urine being substituted with fake urine or adulterated with chemicals to alter the results.
If a prescribed medication causes a positive test result on a DOT test, the Medical Review Officer (MRO) will contact the employee to inquire if there is a legitimate medical reason that would cause a positive result.
If there is a medical reason, the MRO will request a copy of any prescriptions that relate to this medical reason. The MRO will verify the information with the prescribing physician and if it is valid and explains the positive result, the test is reported as negative.
If there is no adequate medical reason given, the MRO will deem the result as positive.
While rare, false positive results can occur due to:
Confirmation testing and the MRO review process help to minimize the risk of false positives.
There are very few exemptions from DOT drug testing. However, some specific situations may exempt certain individuals:
It’s crucial to note that exemptions are rare and specific to each DOT agency’s regulations. These regulations are subject to change at any time. Additionally, each agency will let you know if you are exempt or not during the hiring process.
Tampering of urine specimens can be detected by several methods:
If tampering is suspected, a second attempt will be collected under direct observation.
Refusing a DOT drug test is considered equivalent to a positive test result. Refusal includes:
Consequences of refusing a DOT drug test are the same as receiving a positive result:
If an employee is unable to give the full 45 ml of urine that is required, the following steps will be taken:
If a medical explanation is identified by the physician, the test is cancelled. The physician or MRO will then order a blood test to see if there is evidence of drug use:
DOT testing is only required for industries and jobs that fall under the DOT. Non-DOT testing is for those jobs that do not fall under DOT.
There are some key differences between DOT and non-DOT drug testing. This includes:
Regulated substances: DOT only tests for a specific panel of 5 drugs. Whereas, non-DOT testing can test for those 5 drugs, but also has the flexibility to test for whatever additional substances that they see fit, like Fentanyl or Spice for example.
Collection procedures: DOT tests follow strict protocols outlined in 49 CFR Part 40. With non-DOT collections, the lab normally determines the collection protocol, whether it be Quest, Labcorp, etc.
Consequences: DOT violations have specific, mandated consequences and return-to-duty processes. Consequences for non-DOT violations can vary and are determined by each individual company.
Random testing rates: DOT agencies set minimum annual testing rates for random collections. Companies that do non-DOT testing are free to choose their own annual testing rates.
The DOT Drug Testing program promotes a safe work environment by testing thousands of workers in the transportation industry every year. As regulations change, it’s essential to stay informed about the latest updates and procedures.
1.Robert F. Forman, P., & Paul D. Nagy, M. L. (2006). Substance Abuse: Clinical Issues in Intensive Outpatient Treatment. Retrieved from National Library Of Medicine: https://www.ncbi.nlm.nih.gov/books/NBK64092/
2.Transportation, U. D. (2024, October 3). CFR 49, PART 40—PROCEDURES FOR TRANSPORTATION WORKPLACE DRUG & ALCOHOL TESTING PROGRAMS. Retrieved from Code of Federal Regulations: https://www.ecfr.gov/current/title-49/subtitle-A/part-40
Reader interactions
2 Replies to “DOT Drug Testing Overview”
Great article! I really appreciate the clear and detailed insights you’ve provided on this topic. It’s always refreshing to read content that breaks things down so well, making it easy for readers to grasp even complex ideas. I also found the practical tips you’ve shared to be very helpful. Looking forward to more informative posts like this! Keep up the good work!
Thank you Bernhard!