Can Employers Conduct On-Site Drug Testing?

Yes, employers can conduct on-site drug testing, and many choose to do so as part of their workplace drug testing program. On-site drug testing allows collections to take place directly at the workplace rather than sending employees to an off-site clinic.

For many employers, on-site testing is a practical way to improve compliance, reduce downtime, and strengthen deterrence.

What Is On-Site Drug Testing?

On-site drug testing, sometimes called mobile drug testing, occurs when a certified collector comes to the employer’s location to perform drug test collections. Testing can be conducted in a designated area of the workplace, a mobile unit, or another controlled environment on-site.

The same testing standards and chain-of-custody procedures apply as they would in a clinic setting.

Is On-Site Drug Testing Legal?

In most cases, yes.

Employers are generally allowed to conduct on-site drug testing as long as the testing:

• Follows federal and state employment laws

• Is outlined in a written company policy

• Is applied consistently to employees

For DOT-regulated employers, on-site collections are permitted as long as DOT procedures are followed exactly.

Why Do Employers Choose On-Site Drug Testing?

Many employers choose on-site testing for convenience and control. Common benefits include:

• Reduced employee downtime

• Fewer work disruptions

• Better control over the testing environment

• Lower risk of test tampering

• Faster response for post-accident or reasonable suspicion testing

On-site testing is especially useful for job sites, shift work, and larger crews where sending employees off-site can be disruptive.

What Types of Drug Testing Can Be Done On-Site?

Most common workplace drug testing types can be conducted on-site, including:

• Pre-employment drug testing

• Random drug testing

• Reasonable suspicion testing

• Post-accident drug testing

• Return-to-duty and follow-up testing

The type of test performed depends on the employer’s policy and whether the testing is DOT or non-DOT.

What Drug Testing Methods Can Be Used On-Site?

On-site collections may use different testing methods, such as:

• Urine drug testing, the most common method

• Oral fluid (saliva) testing, often chosen for observed collection

• Instant drug testing, when permitted by policy and law

If laboratory confirmation is required, specimens are sealed and sent to a certified lab after collection.

Does On-Site Drug Testing Improve Deterrence?

For many employers, yes.

On-site testing allows for surprise testing and limits opportunities for employees to delay or avoid testing. This often results in fewer refused tests and less attempted fraud, making the overall program more effective.

Are There Privacy Considerations?

Employee privacy is still a priority with on-site testing. Collections must be conducted discreetly, professionally, and in accordance with privacy standards. Proper procedures help ensure testing is respectful and defensible.

When Is On-Site Drug Testing a Good Fit?

On-site drug testing is often a good option for employers who:

• Have multiple employees or crews

• Operate job sites or shift schedules

• Need rapid post-accident or reasonable suspicion testing

• Want to minimize lost work time

It can be used alone or combined with off-site testing depending on the employer’s needs.

Learn More About Employer Drug Testing Options

On-site drug testing is one of several tools employers can use to support workplace safety and compliance. Understanding when and how it can be used helps employers design an effective testing program.

For more answers to common employer questions, visit our Employer Drug Testing FAQs, where we explain testing options, requirements, and best practices in clear, straightforward language.