Many employers have taken the stance that drug-testing protects the employer from an employee who claims a job-related problem, but whose “real” problem is the use of illicit drugs. In such an environment, any work-related problem is automatically accompanied by drug testing. By writing a policy that has no exceptions, the company cannot be accused of arbitrarily deciding whom to test. Moreover, the company may feel it is more protected against a liability claim brought by an employee whose injury was caused or exacerbated by the use of illicit drugs.
The obvious unfairness is that an employee who uses recreational drugs privately but works unimpaired may test positive for illicit drugs even though they were unrelated to the injury at hand. In a case where the employee simply reported non-specific symptoms, drug-testing can render the cause ambiguous–was it the drug use or the work environment?–providing an additional layer of protection from culpability.
Is it fair or unfair? That may be the topic for a different debate. I suspect there are those who abuse both sides of the equation.
Your drug test (if it was urine) will be a standard battery that likely includes the following:
Amphetamine
Barbiturates
Benzodiazepines (valium family)
Cocaine
Ecstasy (MDMA)
Methadone
Morphine/Opiates
Methamphetamine
Marijuana (THC)
PCP
The test is run from relatively inexpensive standardized kits. If a positive result has a prescription drug as a possible cause, you will be given a (private) opportunity to explain it away.
Good companies need good employees. The farces of our litigious, drug-use obsessed culture are many.