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Random Drug Testing


Having a random drug test policy is considered one of the best tools employers have for deterring drug and alcohol use in the workplace. Employers randomly test employees for compliance with their corporate drug-free workplace policy. Typically, these employees are selected by an outside third-party administrator or a computer program. The random selection process gives an equal probability that any employee from a group of employees will be selected for a test. For example, if a client has eight individuals with a 50% random percentage for a year, then four individuals will get pulled for a random each year.


Commonly cited benefits of random drug testing policies include:

  • Saves lives and prevents injuries
  • Prevents employees from doing drugs in the first place as workplace drug testing acts as a deterrent
  • Reduces employer liability
  • Creates a fair and equal drug testing system for all employees
  • Helps employers identify workers with substance abuse problems and establishes proper treatment plans

Random testing is so effective due to the element of surprise. Although employees are aware that they might be tested, they’re not sure of exactly when so random selections and testing should be performed at least quarterly. However, each company policy differs, and some employers test more frequently than others.

However, random drug testing is ineffective if it does not meet best practices and achieve compliance with regulatory standards. Here are some recommended best practices that employers should consider when implementing a random drug and alcohol testing program.

Practice True Random Selection

A true random selection will require employers to use a statistically random generator, which will ensure an equal probability of selection for individual screening for all employees.

Limit Time Between Notification and Testing

Limiting time between notifying an employee and the actual testing is important to reduce the possibility of the employee evading detection. The less time the employee has to prepare the harder it is for them to cheat. The recommended amount of time between notification and testing should only be the amount of time it will take the employee to get from the business to the testing facility. If a worker does not make it to the testing facility within the allotted time, then it should be considered a refusal to test.

Know Your Clinic's Hours and Policies

Employers and managers who are responsible for drug and alcohol testing notifications should remain up-to-date with the testing clinic’s hours and policies. For example, sending an employee for a random test with only 15 minutes before closing time could jeopardize the test.

Remain Compliant with State and Federal Regulations

It is important to follow state and federal requirements, as laws may vary. If an organization does not follow drug and alcohol testing regulations and remain compliant they may face costly fines.

Adjust Testing to Fit Your Industry

Testing needs will vary by industry, so it’s important to adjust your testing accordingly. DISA can accommodate various industry and policy testing windows whether it’s by days, months, etc. For example: FMCSA allows for quarterly or monthly testing schedules, but with NASAP you have a 9-day calendar window.

Maintain Documentation

It’s important to maintain documentation throughout the entire testing process, as it will better protect your organization in the event of an audit or litigation brought by workers. If an employee is selected multiple times he/she might question the random selection procedures and pursue legal action. Documentation will provide a record of all procedures and policies.


Why are some people randomly tested more than once? 

In a truly random testing selection process, there’s a high probability that some employees will be selected several times while others might never be selected. Why? Because after each selection, all employee’s names are redistributed back into the same pool so that they are just as likely as everyone else to be selected for the next time.

How are employees notified to report for a test?

Employees should be notified as discreetly as possible and according to your company policy. Only a select number of people should have access to the selection list to enforce confidentiality and maintain the element of surprise. Employers should follow best practices and procedures to ensure that the employee has no chance of receiving advanced notice of selection. DISA offers customizable DER access, enabling specific privileges to certain users. For example, one user might have access to only order drug tests, while others can only view test results.

What happens if a selected employee is not available for testing?

Policies must be in place for employers when an employee is unavailable for testing.

  • Best Practices: When an employee is unavailable during a random selection (extended absence, long-term illness, etc.) then the employee should document the reason, and can either choose to make another selection to fulfill the numbers or make an extra selection next cycle.*
  • If an employee is selected for random testing on his/her day off, then the employee can be tested during his/her next shift within the same selection cycle.

*Note: Not all policies allow extra selections or backups, such as NASAP which requires the company and employee to go red until the next pull.

What does an employee need to do when notified of a random test?

Once an employee is notified, he/she must proceed immediately to the collection site. DOT regulations allow 30 minutes plus reasonable travel time.

Maintaining and Evaluating Your Random Testing Program

To maintain best practice, an employer should keep documentation throughout the entire random testing process. This can include the numbers, employees’ names selected, the date and time of notification, reasons why a selected employee was not tested during a selection cycle, date and time of collection, and other pertinent information as required.