Random drug testing should use an unpredictable, neutral selection process—not a supervisor’s preference disguised as randomness. In DOT-regulated programs, covered employees must be selected through a scientifically valid method, testing must be unannounced, and selections must be spread reasonably through the year.
This guide is part of Workplace Drug Testing.
What “random” means
Every person in the defined pool should have the chance required by the program’s selection method. A computer-generated process, random-number table, or qualified consortium/third-party administrator may be used. Names should return to the pool as the rules require, so a person can be selected more than once.
Who belongs in the pool?
Regulated pools should include the employees covered by the applicable agency rule, with correct additions and removals as duties change. Mixing regulated and nonregulated workers improperly can distort selection rates and create compliance problems. Owner-operators and small employers may participate through a consortium under agency-specific requirements.
Notice and reporting
Random testing is ordinarily unannounced. Once notified, a covered employee generally must proceed promptly according to the instruction. Advance schedules should be confidential and accessible only to personnel who need them.
DOT testing
Each DOT modal agency identifies who is covered and the annual random rates. Employers should use the current agency rate and test the correct number of employees. DOT employer guidance says random selections must be scientifically valid, give each covered employee an equal chance, remain unannounced, and be spread reasonably through the calendar year.
DOT random drug testing can occur when the employee is notified, subject to agency rules. Random alcohol testing has timing limits tied to performance of safety-sensitive functions.
Nonregulated random testing
State or local law may restrict random testing to safety-sensitive positions, require notice, or prohibit it in some circumstances. Collective-bargaining duties and employment contracts may also apply. Employers should obtain current jurisdiction-specific advice before starting or expanding a random program.
Random is different from reasonable suspicion
A random test does not require individualized suspicion. A reasonable-suspicion test is based on documented observations under a separate policy or regulation. Mislabeling the reason can affect forms, reporting, and legal defensibility.
Selection fairness and audits
Employers should preserve pool lists, selection records, dates, rates, notifications, completed tests, and explanations for missed or cancelled tests. Periodic audits can identify excluded employees, stale rosters, duplicate identities, inadequate spread, or tests conducted under the wrong authority.
Employee questions
- Am I in a federally regulated or company-policy pool?
- Which agency or state rule applies?
- What specimen and panel are used?
- What conduct is treated as a refusal?
- How are prescriptions and results reviewed?
- Who receives the final result?
Refusals and inability to provide a specimen
Leaving, failing to cooperate, or failing to provide a specimen can be treated as a refusal under defined rules, but medical-evaluation procedures may apply when a person cannot provide sufficient volume. Collectors and employers should follow the rule rather than invent consequences.
Continue with Regulated-Industry Testing and The Collection Process.
Sources
Legal and evidence review: October 29, 2026. Verify the current agency rate and local law.