They are generally acceptable for use in the office practice environment. Some home use drug testing kits are also being sold. These generally are not testing devices themselves, but are specimen containers which are to be filled and sent to a central laboratory, where the actual testing is done. The price of the kit includes the testing. A more recent development is the use of hair as a sample for drug screening.
Hair gives a history of chronic drug use rather than documenting recent usage.
All positive urine screening tests for drugs should be confirmed, especially if any medical, legal, or employment consequences can result from the positive test. GC-MS can identify the specific substance ingested by recognizing not only the molecular structure of the original compound but also its pattern of metabolites. In the confirmatory test, the drugs in the urine sample are isolated on a small chromatographic column, eluted with an organic solvent, and injected into the gas chromatograph-mass spectrometer. The gas chromatograph separates the substances present, and then each substance is broken into molecular fragments by the mass spectrometer. The molecular fragmentation pattern for each substance is unique, allowing for identification of the substance by comparison with a computer library of known fragmentation patterns.