Consortium/Third-Party Administrators (C/TPAs) manage all, or part, of an employer's DOT drug and alcohol testing program, sometimes including maintaining required testing records. They perform tasks as agreed to by the employer to assist in implementing the drug and alcohol testing program and to help keep the employer compliant with the DOT/FMCSA Drug and Alcohol Testing rules and regulations.

A consortium will often manage the DOT random testing programs of several employers, including those of owner-operators who are not permitted to manage random testing themselves. Consortiums that manage owner-operator programs play a very unique service agent role. While §40.355(k) prohibits service agents from serving as "designated employer representatives" (DER), the consortium is authorized to perform a number of employer functions in cases of owner-operators, and single driver employers.

If an employer uses C/TPAs, the rules do not require a written contract, but having a written contract makes good business sense. Due to the number and complexity of drug and alcohol testing program requirements, written contracts or agreements between C/TPAs and employer clients are important to ensure each party understands who is responsible for each program requirement and provides evidence of regulatory compliance. The U.S. Department of Transportation Office of Drug and Alcohol Policy and Compliance publication "What Employers Need to Know About DOT Drug and Alcohol Testing" provides considerations about entering into contracts with service agents. Keep in mind, however, §382.105 requires that each employer ensure that all alcohol or controlled substances testing conducted under this part complies with the procedures set forth in Part 40, and §40.11 provides that employers are responsible for all actions of your officials, representatives, and agents (including service agents) in carrying out the requirements of the DOT agency regulations.