The U.S. Constitution does not prohibit drug testing of employees. However, in the U.S. Supreme Court case of Treasury Employees v. Von Raab, 489 U.S. 656 (1989), the high court ruled that requiring employees to produce urine samples constituted a “search” within the meaning of the Fourth Amendment to the U.S. Constitution. Therefore, all such testing must meet the “reasonableness” requirement of the Fourth Amendment (which protects citizens against “unreasonable” searches and seizures). The Court also ruled that positive test results could not be used in subsequent criminal prosecutions without the employee’s consent.

The other major constitutional issue in employee drug testing involves the Fifth Amendment (made applicable to the states by the Fourteenth Amendment), which prohibits denial of life, liberty, or property without “due process of law.” Since the majority of private-sector employees in the United States (excepting mostly union employees) are considered “at-will employees,” an employer need not articulate a reason for termination of employment. However, under certain circumstances, the denial of employment or the denial of continued employment based on drug test results may invoke “due process” considerations, such as the validity of the test results, the employee’s right to respond, or any required notice to an employee.

Finally, under the same constitutional provisions, persons have a fundamental right to privacy of their person and property. Drug testing, although in itself deemed legal, may be subject to constitutional challenge if testing results are indiscriminately divulged, if procedures for obtaining personal specimens do not respect the privacy rights of the person, or if testing is unnecessarily or excessively imposed.