A saliva-based drug test is similar. It involves swabbing the inside of your cheek and inserting the swab into a test collection device or placing the saliva sample directly onto a special test strip.

For example, United States federal law mandates that people working in the transportation industry take regular drug tests. Laws about employee drug testing differ geographically. A person should ...

More employers are quietly taking what once would have been a radical step: Dropping marijuana from the drug tests they require of prospective employees. (John Locher/AP) Analysis by Jena McGregor ...