Gas Chromatography/Mass Spectrometry

The best and most accurate way to test for drugs today is with gas chromatography/mass spectrometry (GC/MS), which uses $100,000 machines. CG/MS results are very accurate_99.9 percent. Most courts of law accept these drug tests.

GC/MS uses a gas, special chemicals, and electric charges to separate the different chemicals in a urine sample. Drugs, which are chemicals, separate from other parts of the urine. The test is complex and costs a lot_$40 to $70 each. Highly trained lab people must run the machines and analyze the results.

Because GC/MS machines cost so much, most places don't have them. The machines are also big and hard to move around from labs to factories. Many places use the EMIT or RIA tests instead because they are fast and don't cost a lot.