How far back does a mouth swab drug test go back?

Not Medical Advice: Traces of drugs will show in the saliva up to 24 hours after use.

Saliva tests check for alcohol, phencyclidine drugs, opiates, coc@ine, mariju@na, and methamphetamine. If a drug is detected its corresponding band will change color. A negative drug test would show no color at all.

According to the United States Department of Labor, most private employers have the right to administer drug tests to prospective and current employees.

Of interest, Mississippi is making headlines after its governor signed a bill that will force some welfare recipients to undergo drug testing. Those who fail will be required to get treatment before receiving benefits. Learn more from the Memphis Business Journal.

Updated on Wednesday, March 26 2014 at 04:48AM EDT