UPDATED 2020

Drug Test Guide

Drug tests examine a person’s hair, urine, saliva, blood or other fluid for the presence of any kind of drug substance, including illegal drugs, alcohol, prescription medication and non-prescription medication. A drug test, often referred to as a toxicology test or toxicology screen, can check for as many as 30 different drugs at one time.

Drug tests are done for many reasons, including:
  • Employment – Many companies conduct pre-employment drug screening before extending an offer of employment to a candidate. Many companies also conduct random drug testing to ensure their staff is not using illegal drugs.
  • Athletics – Athletes at both the college and professional level are subject to drug testing to ensure fair competition. Athletes who are found to have taken performance-enhancing substances may not be allowed to compete.
  • Emergencies – Drug tests are often used in emergency situations where one is found unconscious or with other symptoms. Understanding what drugs are in a patient’s system is important for doctors to be able to treat the patient’s condition.
Drug tests are often conducted using a urine sample in which a person collects his or her own urine in a cup and submits it for testing. To learn more about how a urine test is conducted, please see our Urine Test Guide. An important note about urine collection for drug tests is that someone may be required to watch the sample collection to ensure that it is your own. Urine samples also may be tested for temperature to ensure it is a fresh sample.
Prior to participating in a drug test, it is important to tell your doctor or tester about any other medications you may be taking, as some medications may alter test results.
Drug tests generally only detect the presence or absence of drugs, rather than the quantity present. A normal result indicates that drugs have not been found. A normal result may also indicate that prescription or non-prescription medication has been detected. An abnormal result indicates that drugs have been found in one’s urine or blood.
Many drug test programs test for five common drugs, including:
  • Amphetamines, including speed and methamphetamine
  • Cannbinoids, such as marijuana and hashish
  • Cocaine
  • Opiates, including morphine, codeine and heroin
  • Phencyclidine
Other tests will check for the five above, as well as:
  • Barbiturates
  • Benzodiazepine
  • Methadone
  • Methaqualone
  • Propoxyphene
If you are considering implementing drug testing in your organization, please see our Drug Test Directory. For more information about drug tests, read our interviews with drug test experts Greg Johnson and Elina Smith.