DOT Rule 49 CFR Part 40 Section 40.17
Subpart B - Employer Responsibilities
§ 40.17 Is an employer responsible for obtaining information from its service agents?
Yes, as an employer, you are responsible for obtaining information required by this part from your service agents. This is true whether or not you choose to use a C/TPA as an intermediary in transmitting information to you. For example, suppose an applicant for a safety-sensitive job takes a pre- employment drug test, but there is a significant delay in your receipt of the test result from an MRO or C/TPA. You must not assume that “no news is good news” and permit the applicant to perform safety-sensitive duties before receiving the result. This is a violation of the Department's regulations.