State laws do not address negative dilute, so it is up to your company policy. DOT regulated companies are advised only one recollection is allowed, and the second collection becomes the recorded result – even if it is another negative dilute. In other words, you are not permitted to require the employee to take an additional test.
Because a negative dilute test result is a negative test for DOT program purposes, the employer is authorized to have the applicant begin performing safety-sensitive functions. So, for non-DOT you can also decide to hire, you do have a negative result. Always be consistent treating all the same on this same issue.
If the employer declines to hire the applicant in this situation, the employer’s decision is based solely on its own policy. The employer cannot claim that its action is required or authorized by DOT rules.
We always recommend that prior to the second collection the employer advises the applicant or employee on how to avoid a dilute specimen. The applicant should avoid drinking any excessive amount of fluids.