Reasonable Suspicion Drug Testing: Signs to Look for and When to Implement 


By: Tarrah Martinez, DISA Global Solutions, Inc. 

To combat drug abuse in the workplace, employers have several ways to secure a safer working environment. A clear, concise, and comprehensive drug testing policy is critical, but employers also need to ensure their management is trained to identify drug and alcohol abuse on the job as soon as it begins.

According to the National Institute on Drug Abuse, “Many individuals who develop substance use disorders (SUD) are also diagnosed with mental disorders, and vice versa. Multiple national population surveys have found that about half of those who experience a mental illness during their lives will also experience a substance use disorder and vice versa.” Due to this link, it is imperative that companies work to prevent substance abuse by their employees and assist them in getting the help they need.

Reasonable suspicion drug testing is often included as part of a company’s comprehensive drug testing policy, allowing employers to drug test an employee based off of evidence of drug use, (e.g., signs, symptoms, and behaviors) under direct observation. This is an added level of protection that remains in effect long after the initial pre-employment screening to continue to deter employees from using in the first place.

What is Reasonable Suspicion Drug Testing?

If an employee is under the influence while on the job, they can pose a great risk for themselves, employers, as well as the employees around them. To determine if an employee has used drugs or is under the influence while at work, employers can implement the procedures associated with reasonable suspicion drug testing. Reasonable suspicion testing, or for cause drug testing, is performed when supervisors have evidence or reasonable cause to suspect an employee of drug use. When building a company drug testing policy, it’s vital that employers include reasonable suspicion testing so that employees fully understand the rules and so that employers know how to address such issues when they arise. A proper drug testing policy will ensure that certain supervisors or employees are trained to detect drug use in the workplace, as well as how to implement the steps to reasonable suspicion itself: observing the employee, how to confront the employee, properly documenting the incident, and implementing the drug testing procedures.

  • Observe—Employers must decide which supervisors or employees will receive reasonable suspicion training.
  • Confront—Individuals should also be trained on how to confront the employee in a professional and discrete manner.
  • Document—Employers should prepare a way for supervisors to properly document the incident to further prevent litigation risks.
  • Implement testing— Employers should have a clear and concise drug testing policy that includes reasonable suspicion testing and implementation procedures if an employee is required to do so.

When to Implement a Reasonable Suspicion Drug Test

If an employee is suspected to be under the influence, then a trained supervisor or manager may observe the employee using the signs below to help them determine if a reasonable suspicion drug test should be administered. Any time an employer feels it is necessary to administer a reasonable suspicion drug test, all information should be documented to meet compliance standards. The following are valid reasons to conduct a reasonable suspicion test:

  • Physical signs—Bloodshot eyes/dilated pupils, slurred speech, unsteady walk, shakes or tremors, unexplained sweating or shivering, fidgeting/inability to sit still, sleeping at work or difficulty staying awake
  • Behavioral signs— Attendance problems/ tardiness, a pattern of absences or excessive absenteeism, a decline in performance/productivity, acting withdrawn from others
  • Psychological signs— Unexplained changes in personality or attitude, sudden mood changes, angry outbursts or inappropriate laughing, inability to focus or concentrate

What Can Employers Do?

When creating and implementing a comprehensive drug testing policy, employers should include reasonable suspicion testing to prevent drug abuse in the workplace. This should be in addition to other methods of testing, such as pre-employment, random, post-accident, and Return-to- Duty (RTD).

“Employers have the opportunity to customize their company drug testing policy to ensure safe hires and prevent accidents from happening. An insufficient policy can compromise your company and employee’s safety, which is truly not worth the risk.” —Frank Bernard VP of Compliance at DISA Global Solutions

DISA offers reasonable suspicion training to help companies maintain a safe working environment by ensuring that your Designated Employee Representative (DER), along with other managerial staff are fully prepared to address drug abuse and use in the workplace. When paired with other drug testing methodologies, proper documentation, and properly trained supervisors, reasonable suspicion drug testing will strengthen a company’s drug testing policy.

Best Practices

Here are a few best practices your company can follow when implementing reasonable suspicion drug testing in the workplace:

  • Include and implement reasonable suspicion drug testing in a clear and concise company drug testing policy.
  • Notify all employees that they are subject to reasonable suspicion drug testing according to the company policy.
  • Ensure the right personnel at your company receives reasonable suspicion drug testing training.
  • Always document all signs and symptoms leading up to and during a reasonable suspicion drug test.
  • If an employee is sent off-site for a reasonable suspicion drug test, do not allow them to drive themselves (especially a company car). This increases your liability because you already believe they may be under the influence.

Creating an all-encompassing drug testing policy helps to decrease absenteeism, accidents and turnover, while increasing company morale and productivity.

Author Bio:

Tarrah Martinez is the Digital Marketing Content Strategist for DISA Global Solutions, an industry-leading drug testing company for over 30 years. DISA helps companies make more informed staffing decisions by offering a broad array of industry-leading methodologies to make employee screening faster and more accurate. Tarrah has over seven years of professional writing experience and uses her expertise to educate readers on the drug testing industry and compliance with the DOT regulations.

Founded in 1987, DISA is the industry-leading provider of employee screening and compliance services. Headquartered in Houston, with more than 30 offices throughout the U.S. and Canada, DISA’s comprehensive scope of services includes drug and alcohol testing, background screening, occupational health, and transportation compliance. DISA assists employers in making informed staffing decisions while building a culture of safety in their workplace.

Are you an employer and still have questions regarding employment screening? Get answers directly from DISA’s subject matter experts with ‘Ask DISA’. Visit to ask your questions today! For more information about how we can help you as a strategic compliance partner and an informed employer, call 1-800-752-6432 or email This email address is being protected from spambots. You need JavaScript enabled to view it..