Reasonable Suspicion Drug Testing: What Supervisors Must Know

What Is Reasonable Suspicion Testing?

Reasonable suspicion drug and alcohol testing — sometimes called "for cause" testing — is ordered when a trained supervisor directly observes an employee displaying signs and symptoms of drug or alcohol use on the job. Unlike random testing, it's triggered by specific behavioral observations, not chance.

Under DOT regulations, reasonable suspicion testing is mandatory for safety-sensitive employees when supervisors observe the required indicators. For non-DOT employers, it's governed by company policy.

What Qualifies as Reasonable Suspicion

The supervisor must observe specific, articulable signs and symptoms of drug or alcohol use. These may include:

Physical signs:

• Slurred speech
• Glazed, bloodshot, or watery eyes
• Dilated or constricted pupils
• Unsteady gait or loss of coordination
• Smell of alcohol or marijuana

Behavioral signs:

• Erratic or unusual behavior
• Marked changes in performance
• Falling asleep on the job
• Excessive agitation or aggression

A hunch, rumor, or suspicion based on an employee's past history alone is not sufficient. The observations must be of current signs and symptoms — not something another employee reported, and not based on hearsay.

DOT Requirements for Supervisor Training

Under FMCSA regulations, at least one supervisor of DOT-covered employees must complete training in recognizing the signs and symptoms of drug and alcohol use before ordering a reasonable suspicion test. The training must cover:

• At least 60 minutes on drug use signs and symptoms
• At least 60 minutes on alcohol misuse signs and symptoms

This training is a one-time requirement, not annual. But maintaining documentation that it was completed is essential for DOT compliance.

Documenting the Observation

Documentation is critical. Before ordering a reasonable suspicion test, supervisors should write down:

• Date, time, and location of the observation
• Specific behaviors, physical signs, and symptoms observed
• Names of any witnesses (a second supervisor observation is best practice, though not always required)
• Any statements made by the employee

This documentation protects the employer in the event of a challenge or grievance.

The Testing Process

Once a reasonable suspicion determination is made, the employee must be sent for testing immediately — or as soon as possible. For alcohol testing, the test must occur within 2 hours (and no later than 8 hours). For drug testing, within 32 hours.

The employee should not drive themselves to the collection site. Arrange transportation.

What Happens If You Don't Test

Failing to conduct a required reasonable suspicion test when the indicators are present creates both compliance and safety liability. The documentation you created becomes evidence that you knew something was wrong and failed to act.

Non-DOT Reasonable Suspicion Programs

Non-DOT employers can implement reasonable suspicion testing through their written drug-free workplace policy. The key elements are:

• Clear definition of what constitutes reasonable suspicion
• Supervisor training requirements
• Documentation procedures
• Consistent application across all employees

At Do It Right Screening, we provide supervisor training documentation support and coordinate reasonable suspicion testing. Contact us to review your program.