The drug testing lab first performs a preliminary screening test on all samples using an Olympus AU-800 Automated Chemistry Analyzer. All negative specimens are discarded after this round. Any urine sample that shows a positive indication of drug use is retested using the same equipment. If that sample also provides a positive result, the lab uses gas chromatography to identify the specific drug in the urine sample. The lab reports a positive result only if all three samples test positive.
What does all that mean? Basically, there’s little chance they’re going to make a mistake.