Responsible employers and business owners in this day and age probably know that there are many benefits of employment drug testing, but they may not be aware of exactly when to test under various circumstances. The most commonly used method of employment drug testing is the pre-employment screening, which occurs during the hiring process. Many employers also utilize random or periodic drug testing to ensure that long term employees are not using illicit substances. There are, however, other times which may compel an employer or business owner may wish to test his workforce for drugs or alcohol.

Reasonable suspicion testing is used by employers who have a legitimate reason to think an employee is using drugs. Observable symptoms of drug use, erratic behavior, or excessive absenteeism can all provide a basis for reasonable suspicion testing. Post-accident drug testing is used in the immediate aftermath of an on the job accident. This type of employment drug testing is crucial because, more often than not, on the job accidents result in property damage or personal injury. In these cases, liability becomes the main issue and determining if any of the parties involved were influenced by drugs or alcohol can protect employers from unscrupulous lawsuits or worker’s compensation claims. Return to duty drug testing is used when an employee is returning to work from a long period away, perhaps for maternity leave or a personal sabbatical. This type of employment drug testing should also be used for employees who have failed a drug test previously and have completed the necessary counseling and recovery efforts.

http://www.dol.gov/asp/programs/drugs/workingpartners/dfworkplace/dt.asp