DOT drug and alcohol testing procedures are the uniform rules in 49 CFR Part 40 that control how every DOT-required test is collected, analyzed, reviewed and reported. Whether a test is ordered for a truck driver, a pilot, a transit operator or a pipeline worker, Part 40 sets the same chain of custody, laboratory standards and review steps. That consistency protects safety-sensitive employees from unfair results and protects the public from impaired workers.
Employers do not get to choose these procedures. FMCSA's rule in Part 382 decides who is tested and when, while Part 40 decides how. Employers, collectors, laboratories, medical review officers (MROs), substance abuse professionals (SAPs) and third-party administrators must all follow it.
What Is 49 CFR Part 40?
49 CFR Part 40, Procedures for Transportation Workplace Drug and Alcohol Testing Programs, is issued by the Office of the Secretary of Transportation and administered by DOT's Office of Drug and Alcohol Policy and Compliance (ODAPC). It applies across the DOT agencies, including FMCSA, FAA, FRA, FTA, PHMSA and the Coast Guard. Each agency's own rule, such as FMCSA's Part 382 for CDL drivers, points back to Part 40 for procedures.
Key definitions and roles include:
- Designated employer representative (DER): the employee authorized to receive results, remove workers from safety-sensitive duty and make required decisions. A service agent cannot act as the DER (40.15).
- Collector: a trained person who instructs and assists employees at the collection site and fills out the custody and control form.
- Medical review officer (MRO): a licensed physician who reviews and verifies laboratory results before the employer sees them.
- Substance abuse professional (SAP): the professional who evaluates employees who violate a DOT rule and decides what education, treatment and follow-up testing they need.
- Service agent: any company or person that provides testing services, such as collection sites, laboratories, MROs and consortia/third-party administrators.
Who Must Comply?
Part 40 applies to every employer that is required by a DOT agency rule to test safety-sensitive employees, and to every service agent that works on those tests. For motor carriers, that means any employer of CDL drivers covered by Part 382, including owner-operators.
Under 40.11 and 40.15, employers remain responsible for compliance even when they outsource the work. Relying on a service agent in good faith is not a defense if the agent gets it wrong.
Part 40 also requires that DOT tests stay separate from company tests (40.13). Employers may run their own non-DOT testing under company policy, but they cannot use DOT custody forms for it, cannot test DOT specimens for anything beyond the DOT panel, and cannot override a verified DOT result with a non-DOT test.
Key Requirements
Specimen collection
Collectors must complete qualification training and a proficiency demonstration before collecting, and refresher training at least every five years (40.33). Each urine collection uses the federal custody and control form and a split-specimen system, so a second bottle is available if the employee challenges a result.
Direct observation is required in specific cases, including all return-to-duty and follow-up tests and certain collections where tampering is suspected or a specimen's temperature is out of range (40.67). The observer must be the same sex as the employee.
Laboratory testing
DOT urine specimens must go to a laboratory certified by the Department of Health and Human Services. Under 40.82, laboratories test for five drug classes:
- Marijuana metabolites
- Cocaine metabolites
- Amphetamines
- Opioids
- Phencyclidine (PCP)
Laboratories may not test DOT specimens for any other drug. Cutoff concentrations for the initial and confirmation tests are listed in 40.85. Every specimen also gets validity testing, such as creatinine, pH and oxidizing adulterant checks, to catch dilution, adulteration or substitution (40.87). Positive, adulterated, substituted or invalid specimens are kept by the laboratory for at least one year.
MRO review
Every laboratory drug test result goes to the MRO, not the employer. For non-negative results the MRO interviews the employee to look for a legitimate medical explanation, such as a valid prescription, before verifying the result. MROs must be licensed physicians, pass a qualification exam and complete requalification training and an exam every five years (40.121).
Alcohol testing
Alcohol tests are done by trained breath alcohol technicians or screening test technicians using approved devices. A positive screening result must be confirmed on an evidential breath testing device before it counts.
Refusals and shy bladder
Part 40 lists conduct that counts as a refusal to test (40.191), including failing to appear within the time the employer sets (except for a pre-employment test), leaving before the test is complete, failing to cooperate, refusing an observed collection, possessing a device to tamper with the specimen, or admitting to adulteration or substitution. A refusal carries the same consequences as a positive test.
If an employee cannot provide at least 45 mL of urine, the collector may give up to 40 ounces of fluid over a period of up to three hours (40.193). If the employee still cannot provide enough, the DER must direct a medical evaluation within five days. Without an adequate medical explanation, the MRO reports a refusal.
SAP and return to duty
An employee who violates a DOT rule must be removed from safety-sensitive work and given a list of qualified SAPs. Under Subpart O, the SAP evaluates the employee, recommends education or treatment, and conducts a follow-up evaluation. The employee must pass a directly observed return-to-duty test. The SAP then sets follow-up testing: at least six unannounced tests in the first 12 months back on duty, and possibly more for up to 60 months total (40.307). The employer may not add its own testing on top of the SAP's plan.
Recordkeeping and Previous Employer Checks
Under 40.333, employers must keep:
- Five years: alcohol results of 0.02 or higher, verified positive drug results, refusal documentation, SAP reports and all follow-up testing records.
- Three years: drug and alcohol information obtained from previous employers under 40.25.
- Two years: inspection, maintenance and calibration records for evidential breath testing devices.
- One year: negative and canceled drug results and alcohol results below 0.02.
Before a new hire performs safety-sensitive work, 40.25 requires the employer to obtain written consent and request the employee's DOT testing records from the past two years. For drug and alcohol history held by other FMCSA-regulated employers, motor carriers use the Drug and Alcohol Clearinghouse. Part 40 also limits release of test information without the employee's written consent (Subpart P).
Recent Changes to Watch
DOT amended Part 40 in 2023 to allow oral fluid testing as an alternative to urine. However, oral fluid tests cannot be performed until HHS certifies at least two laboratories, and HHS's most recent laboratory lists, as of fall 2026, show none certified for oral fluid. A DOT final rule effective June 10, 2026 adds procedures for when a directly observed collection is needed and no same-sex observer is available. DOT also proposed adding fentanyl and norfentanyl to the drug panel in September 2025. As of this writing that proposal is not final, so check ODAPC before changing your program.
Common Compliance Mistakes
- Mixing DOT and company tests. Using a DOT form for a non-DOT test, or adding extra drugs to a DOT specimen, is prohibited.
- Not overseeing service agents. Employers are responsible for collector, laboratory and MRO errors.
- Skipping direct observation. Return-to-duty and follow-up urine collections must be directly observed.
- Adding testing beyond the SAP plan. Extra company-imposed follow-up tests are not allowed.
Violations of Part 40 by FMCSA-regulated employers are enforced under the agency's own rules, and 382.507 makes them subject to civil and criminal penalties.
How to Comply: Step by Step
- Name a DER. Choose a trained company employee, plus a backup, to receive results and act on them.
- Vet service agents. Confirm collectors are trained, laboratories are HHS-certified and MROs and SAPs are qualified, and keep that documentation.
- Keep DOT and non-DOT programs separate. Use separate forms, policies and records.
- Write a post-violation procedure. Cover immediate removal, the SAP list, return-to-duty testing and follow-up scheduling.
- Track follow-up plans. Schedule each SAP-directed test and confirm it is directly observed.
- Request previous employer records. Obtain consent and complete the two-year history check before safety-sensitive work begins.
- Retain records correctly. Apply the one-, two-, three- and five-year periods in 40.333.
- Monitor updates. Review ODAPC notices on oral fluid and the drug panel at least quarterly.
How SMS360 Helps
SMS360's DOT Compliance tools give fleets one place to keep drug and alcohol testing documentation alongside each driver's file. Teams can store custody forms, MRO results, SAP reports and previous employer responses, set reminders for follow-up tests and record retention dates, and assign and track corrective actions when an audit finds a gap.
Dashboards and document storage make it easier to show an auditor the full trail from original test to follow-up testing.
Frequently Asked Questions
What drugs are on the DOT 5-panel test?
Under 49 CFR 40.82, DOT tests for marijuana metabolites, cocaine metabolites, amphetamines, opioids and phencyclidine (PCP). Laboratories may not test DOT specimens for other drugs. DOT proposed adding fentanyl in 2025, but that change had not been finalized as of this writing.
Can a DOT drug test be done with oral fluid?
Part 40 allows oral fluid testing, but it cannot be used until HHS certifies at least two oral fluid laboratories. As of fall 2026, HHS reported that no laboratories were certified for oral fluid. Until that changes, DOT tests use urine.
How many follow-up tests are required after a DOT violation?
The SAP must require at least six unannounced, directly observed follow-up tests in the first 12 months after the employee returns to safety-sensitive work. The SAP can extend testing for up to 60 months in total. The employer schedules the test dates but cannot add tests beyond the SAP's plan.
How long must employers keep DOT drug test records?
Under 40.333, positive results, refusals, alcohol results of 0.02 or higher, SAP reports and follow-up records are kept for five years. Previous employer information is kept for three years, breath testing device records for two years, and negative or canceled results for one year.
