Disclaimer
adopt a written policy - some employers are obligated by law to have written drug-free workplace policies (federal contractors and employers with at least 15 employees who have workers' compensation coverage)
give the policy to all employees in writing - have employees acknowledge receipt
if drug or alcohol testing is done:
pre-employment, random, post-accident, and "for cause" testing are all allowed in Texas and many other states
specific drug test results should be obtained from the testing lab - do not use a lab that is not willing to give you a copy of the results and the chain of custody of the sample
preferably, use a nationally-certified testing lab that will follow strict procedures and furnish complete documentation to support the employer in case a claim or lawsuit is filed - the documentation should show at least the following:
type of tests performed
types and concentrations of substances found
initial results confirmed by GC/MS (gas chromatography/mass spectrometry) method
chain of custody showing who handled the sample at all pertinent times - this is for dealing with the common excuse that the samples must have been switched
For a sample policy on drug and alcohol testing, click here.