June 27, 2025

The Relationship Between a DER and MRO

By NDASA

By: Jonathan Baktari MD, US Drug Test Centers

Multiple professionals play a role in any company’s drug-free workplace program. Two of them are the designated employer representative (DER) and the medical review officer (MRO). What do these specialists do, and how do they work together? Many people (including DERs) wonder what the exact nature of this relationship is, so let’s break down not only what roles a DER and MRO serve, but also how they interact when it comes to a company’s drug testing program.

What is a Designated Employer Representative?

A designated employer representative is the person (or multiple people) responsible for managing a company’s drug testing program. This role cannot be outsourced and must be assigned to an employee of the company (or the owner).

The DER for non-DOT employers is the person in charge of the drug testing program. This person plays a vital role for any non-DOT employer and is a requirement for companies regulated by the Department of Transportation that employ safety-sensitive employees. Commonly, someone from human resources or the safety department will be selected for the DER role.

When it comes to managing the company’s drug testing program, the DER is authorized to remove safety-sensitive employees from their positions, make decisions involved in the testing process, collect drug and alcohol test results, report results to their agency and/or state, and act as the liaison for any agents they work with. (More on this last one in a moment!)

The DER is critical to maintaining a company’s program, and they should undergo training to help them understand how to do this very unique and important job. For instance, US Drug Test Centers offers online training to provide a thorough education on the DER’s duties as outlined by the Department of Transportation’s regulations for drug and alcohol testing. DERs will learn more about the relevant terminology, modal regulations, and procedures for their workplace testing program.

What is a Medical Review Officer?

A medical review officer is a licensed physician who specializes in substance use and abuse. Often, they have a certification in medical toxicology or pharmacology. This means that they have thorough knowledge of how to work with prescription drugs that may affect the outcome of the laboratory testing. They are typically certified by national associations, including the American Association of Medical Review Officers (AAMRO) or the Medical Review Officer Certification Council (MROCC).    

The MRO is an objective third party who can confirm that drug test results are accurate and fair. They review and evaluate test results, both positive and negative, and—in the case of positive results—provide feedback and information about next steps so the company and employee have a better idea of what’s about to happen.

Other times, an MRO may need to refute false-positive test results, which can happen when a prescription medication indicates the presence of drugs, even though the employee didn’t take any illicit drugs.

In any case, the MRO oversees the testing process to ensure that it’s accurate and fair, guides employees who test positive, and protects both employees and the employer.

How do a DER and MRO work together?

Confidentiality and privacy are paramount, leaving many DERs to ask: “Am I allowed to speak to our MRO?”

Not only are you allowed to communicate with your MRO, but you should stay in close contact with them. This relationship is vital to the success of your drug-free workplace program.

Remember what I mentioned earlier: DERs are the liaison, which means that they’re expected to communicate with TPAs, C/TPAs, collection sites, labs, SAPs, and—you probably guessed it—MROs. Primarily, you will interact with this professional when they send you test results, whether they are positive, there’s a refusal to test, or they’re negative, including negative test results that might still note a safety concern (for example, if the employee is taking a prescription medication that may pose a risk to their job duties).

The efficacy of your drug testing program hinges on a few key factors, including having a solid relationship with your MRO so that you receive test results and the appropriate guidance in a timely manner. 

How is an MRO selected for a company?

Employers should consider several factors when choosing an MRO to work with. First, review all their qualifications, licenses, memberships, and any other relevant training or certifications to confirm they meet the minimum requirements.

You should also ask them how they stay on top of changing policies and practices. For instance, do they attend conferences, undergo yearly training, etc.?

Selecting an MRO isn’t a decision to be taken lightly. Don’t be afraid to be picky and have high standards. The medical review officer you ultimately partner with is an investment not just in your drug-free workplace program but your company as a whole.

Keeping a company drug-free takes teamwork

The relationship between the MRO and DER isn’t the only one that matters. TPAs, SAPs, labs, and other parties are directly involved in the success of the company’s drug-free workplace program. Everyone has a unique part to play, and only when all parties can rely on each other can the company’s program be effective.

Do your due diligence and take the time you need to build the team that will best support your business for many years to come.

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