Many may not be aware of the difference between a drug screening and confirmatory drug testing. A drug screen is the first step of the drug testing process. A screening tests for the presence or absence of a select number of drug classes or drugs. This is an efficient and cost-effective way to set preliminary results, allowing any aberrant results to go on to the next step.
If any results come back inconsistent, the next step is confirmatory drug testing. This is done using Gas Chromatographic Mass Spectrometry (GC/MS), which is the gold standard for drug testing.