Employers that advertise hair testing deter drug-using applicants that just stay away. It's impossible for regular users to prepare for it." On the other hand, it typically does not do a good job at detecting sporadic usage..
According to the results of the study, hair follicle drug testing correctly identified: 52.3 percent of people who reported recent marijuana use. 65.2 percent of people who reported recent cocaine use. 24.2 percent of people who reported recent amphetamine use Official KFC Survey