Many institutions require drug screening, from businesses and private schools to the military and probation courts. And maybe for good reason, as one could argue the dangers of, for instance, a construction worker or naval shipmate putting him or herself and coworkers at risk if impaired by drugs. Many also frown upon the use of controlled substances among those who receive taxpayer-funded handouts from social welfare programs. Though drug screens may be despised by some, they do lend themselves to some interesting science. The following details how drug use is identified at the molecular level.
The five most commonly screened drugs, known as the NIDA 5, are cannabinoids, cocaine, amphetamines, opiates, and PCP. A variety of methods exist when screening for drug use. Recent use can be identified in blood and saliva. In contrast, hair samples can reveal a long-term history of use.
When drugs are consumed, they circulate in the bloodstream and are broken down into their respective metabolites. As the blooodstream feeds hair growth, molecules are deposited into the follicle, forming the hair shaft. A sample of hair can provide both the pattern and severity of use.
While blood and saliva tests are limited to recent