If you want to find out more about what are the consequences of a refusal to test, the following is summarized from DOT Rule 49 CFR Part 40 Section 40.191 As an employee, you have refused to take a drug or alcohol test if you: Fail to appear for any test (except a pre-employment [...]

If you want to know what is an MRO (Medical Review Officer), you should that that this is a person "who is a licensed physician and who is responsible for receiving and reviewing laboratory results generated by an employer's drug testing program and evaluating medical explanations for certain drug test results. As a MRO, [...]