49 CFR § 40.273 - What is the effect of a cancelled alcohol test?
(a) A cancelled alcohol test is neither positive nor negative.
(2) As an employer, you must not use a cancelled test in a situation where an employee needs a test result that is below 0.02 (e.g., in the case of a return-to-duty or follow-up test to authorize the employee to perform safety-sensitive functions).
(3) As an employer, you must not direct a recollection for an employee because a test has been cancelled, except in the situations cited in paragraph (a)(2) of this section or other provisions of this part.
(b) A cancelled test does not count toward compliance with DOT requirements, such as a minimum random testing rate.
(d) A cancelled DOT test does not provide a valid basis for an employer to conduct a non-DOT test (i.e., a test under company authority).