While you are considering how best to develop an employee screening program, there are many factors to consider.  Here are two documents that may be of assistance in developing your program.

Questions for Vendors Providing Drug Testing Services

Questions for Vendors Providing Employment Screening

“Are You Enabling Negligent Referral Against Prior Employers?”

In addition, you may want to check with the US Department of Labor and their suggestions on how to establish a drug-free workplace.