See Also: CDL Drug & Alcohol Test Methods & Detection Times Technically, a trucking company could test back 30 days for every 1/2-inch of hair, if they wanted to. Substances will remain in the hair and detectable until that section of hair is cut off. A failed hair follicle drug screen CAN and MAY be reported on your DAC report as a failed test, depending on the trucking company's policy.ĭetection Time: Hair follicle testing can detect traces of illegal substances from as recently as 10 days to as far back as 90 days (using a typical 1 1/2-inch hair sample) from their use or ingestion, which is the standard length many companies will use. Results cannot be reported to the DOT as a failed test, nor can they be shared with other companies.
Currently, hair follicle drug testing cannot be used by trucking companies to satisfy Federal DOT drug testing requirements but can be used internally as a prerequisite of employment.
