The first thing to know about drug testing is what the standard test looks for. What is being tested for varies greatly based on testing company, expense, expectations, federal requirements, etc. Following is a description of what to expect from the standard tests.

Federal government guidelines (by SAMHSA-the Substance Abuse and Mental Health Services Administration) require that companies which use commercial class drivers licenses for employees must have a testing system in place. Among other things, this required testing program must test for 5 specific categories of drugs (referred to as the “SAMHSA 5″, previously called the “NIDA-5″). Because of this federal requirement, most drug testing companies offer a basic drug test that checks for drugs in these 5 common categories. Click on the substance name for a description of the laboratory method for detecting the substance.

1. Cannabinoids (marijuana, hash)
2. Cocaine (cocaine, crack, benzoylecognine)
3. Amphetamines (amphetamines, methamphetamines, speed)
4. Opiates (heroin, opium, codeine, morphine)
5. Phencyclidine (PCP)

Expanded Tests
Most drug testing companies also offer an expanded test which includes a few additional drug classes and specific drugs in the testing process. Most do not add all of these in their expanded test, but choose a different combination of 3 or 4 to add :

1. Barbiturates (Phenobarbital, Secobarbitol, Butalbital)
2. Hydrocodone (Lortab, Vicodin)
3. Methaqualone (Quaaludes)
4. Benzodiazepines (Valium, Xanax, Librium, Serax, Rohypnol)
5. Methadone
6. Propoxyphene (Darvon compounds)
7. Ethanol (Alcohol)
8. MDMA (Ecstasy)

Additional Testables
In addition, there are a few other substances which it is possible but quite unusual to test for. I only found reference to testing for these additional substances at 1 (out of 15) drug testing sites :

1. LSD
2. Tryptamines (Psilocybin, AMT, DMT, DPT, 5-MeO-DiPT)
3. Phenethylamines (Mescaline, MDMA, MDA, MDE, 2C-B, 2C-T-7)
4. Inhalents (Toluene, Xylene, Benzene)