The most common reason employers drug test is pre-employment. With a pre-employment drug test employers protect themselves from the negative impact of hiring a drug user thereby improving their workplace productivity and protecting themselves from numerous liabilities. A pre-employment drug test is given to job candidates after an offer is extended. A pre-employment drug test can either be Hair, Oral or Urine depending on your workplace drug-testing policy. In some states, businesses can benefit from reduced workers compensation premiums if they have a compliant drug-free workplace policy that includes pre-employment drug testing.