According to Lab Tests Online, drug screening usually begins with an initial test, followed by a confirmatory or quantitative test. Detecting drugs on a drug screen depends on the type of screen performed. Urine, blood, hair, sweat and saliva panels detect sets of drug metabolites. Urine drug screens are the most common and are usually set up to detect drugs of abuse. Specific panels can be set up to detect performance-enhancing drugs. Nearly all drugs and supplements produce metabolites that are detected by drug screening.
Stimulants
Stimulants, which include amphetamines, cocaine and methamphetamines, are detected in drug screens. A cut off level is set for the drug screen panel and if the metabolite exceeds the level, the screen is considered positive for the metabolite in question. Below the level, the screen is considered negative. Each drug has its own cut off level. According to Drug and Alcohol Testing Compliance Services, the cut off detection level varies.
Depressants and Sedatives
Alcohol in any form is detected in a drug screen panel. Panels can be set up to test just for depressants and sedatives, while eliminating the test for alcohol. The decision is made according to the drug testing requirements of individual companies.
Barbituates, benzodiazepines, ethanol, ethchlorvinyl, flunitrazepam, gamma-hydroxybutyrate, glutethimide, meprobamate, methaqualone and methyprylon are some of the drugs a screening might reveal.
Dissociative Drugs
Ketamine and Phencyclidine are detected in drug screens. Ketamine is a veterinary drug prescribed for horses as an anesthetic. The effects in humans are very similar to PCP. Taking veterinary drugs does not mean they will escape detection on a drug screen.
Opiates
Opiates are commonly abused drugs as they are frequently prescribed by doctors. Testing positive for a prescription drug will result in a call from the medical officer of the drug testing company to confirm a current valid prescription. If the drug is legally prescribed, the medical officer will give the drug screen a passing grade.
Oxycodone, fentanyl, heroin, hydromorphone, methadone, codeine, morphine, pentazocine and propoxyphene are detected in drug screens.
Psychedelics
Lysergic acid diethylamide, mescaline and psilocybin are detected in drug screens. Native Americans and some religious groups have protested the inclusion of psychedelics in drug screens. Laws made to suppress the use of LSD, mescaline and peyote buttons have been declared unconstitutional in several states on the grounds they have violated constitutional guarantees of freedom of religion.
Cannabinoids
THC, hash oil, hashish and marijuana are detected in drug screens. Cannabinoids are detected long after the effects have worn off and may continue to be detected weeks and months after ingestion.
Sports Drugs and Doping
Substances taken by athletes to improve performance are often the target of a drug screen. Anabolic steroids, beta blockers, erythropoietin, peptide hormones, growth hormones and human chorionic gonadotropin are all detected by drug screening. Creatine kinase is another such supplement, but it is detected using special equipment.
Designer Drugs
So-called "designer drugs" are often created in an effort to avoid detection by drug screening. According to the Encyclopaedia Britannica, designer drugs are synthesized in an attempt to create an analogue of some better-known chemical. New names are invented to confuse the public. Drug screens are set up to detect metabolites of drugs, not just the drugs themselves. Metabolites are substances produced by the body from the ingestion of the different classes of drugs. Creating a designer drug will not prevent detection of drug abuse.
