[9] JAMA, November 28, 1990 Vol 264(20) pp 2676-2677 “Pre- employment Drug Screening” by Eric D. Wish, Ph.D


... factors suggest that pre-employment drug testing may have limited potential in the United States. First, employers should remember that a single positive urine test provides limited information about a particular employee's level of drug use. ... Furthermore, lifestyle issues may contribute to an employee's drug use as well as to his or her poor job performance.


Unfortunately, a medical review officer-type review is not required for firms testing private sector employees, and job applicants may be denied positions on the basis of a single positive test result, without their knowledge and without the right of appeal.