What is a Drug Screen?

Morgan Grant | Last updated 06/21/2023

A drug screen (also called a drug test) is the collection and analysis of blood, urine, hair, saliva, or another specimen type to evaluate for the presence of chemicals and contaminants left behind in the body after drug use. A drug screen may also be used to detect performance-enhancing drugs (PEDs), such as steroids and human growth hormone (hGH), sometimes used illegally by professional athletes. Many different types of drug screens exist for multiple purposes.

Most Common Types of Drug Screens

Urine Drug Screen

Urine drug screens are the most popular type of drug test performed today, in part due to their low cost and simple collection process, with around 90% of employers preferring urine tests as of 2018.1 The specimen collection usually happens at a clinic or testing facility, and the sample is then sent to a lab for processing. Depending on the type of panel used – a 5-panel or 10-panel urine test, for example – the specimen will be evaluated for a specific set of prescription drugs and/or illegal substances. 

For employee drug screening – whether for pre-employment purposes, random drug testing, cases of reasonable suspicion, or otherwise – the 5-panel drug test is used most often by employers.2

5-panel urine drug tests screen for:

  • Amphetamines
  • THC (cannabis, cannabinoids)
  • Cocaine
  • Opioids
  • Phencyclidine (PCP)

The more comprehensive 10-panel urine drug test can be used to detect: 

  • Amphetamines
  • THC (cannabis, cannabinoids)
  • Cocaine
  • Opioids
  • Phencyclidine (PCP)
  • Barbiturates
  • Benzodiazepines
  • Methaqualone
  • Methadone
  • Propoxyphene

Saliva Drug Screen

Also known as an oral fluid drug screen, the saliva drug test uses a less invasive collection process involving a swab of the mouth, which may be self-performed under direct clinical supervision. However, the drug detection period for saliva is shorter than that associated with other specimen types. For example, the window of detection for THC in saliva can be as short as 2-48 hours after use, whereas THC may show up in urine, hair, and other sample types many days, weeks, or even months after use.3 This offers a unique opportunity for employers to differentiate between recent (on-the-job) substance use and prior use with oral fluid drug testing, particularly in states where certain drugs – like cannabis – have become legalized.

Additional substances that may be detected on a saliva drug screen include marijuana, cocaine, opiates, alcohol, amphetamine, methamphetamine, (including ecstasy), and PCP.

Blood Drug Screen

Blood testing is the least popular of the drug screen methods,  which is likely due to its more invasive nature, shorter detection window, and higher price tag compared with other drug testing methods. However, similar to oral fluid drug testing, blood tests can be useful for detecting impairment and/or substance use on the job, as toxins can show up in the blood within minutes or hours of drug use. Blood testing is also capable of measuring the specific amount of an illegal substance in a person’s system4, helping employers or law enforcement to understand their level of impairment and whether they may be over the recommended or legal limit of certain substances. Some of the substances that can be detected on a blood drug test include ethyl alcohol, amphetamines, barbiturates, benzodiazepines, cocaine and metabolite, phencyclidine, THC, opiates, oxycodone, methadone, fentanyl, buprenorphine, propoxyphene, meperidine, tramadol, gabapentin, and carisoprodol.

Hair Drug Testing

A strand of hair acts as a timeline of a person’s substance intake history. Someone could have used marijuana months ago, yet through hair drug testing, the substance would still be detectable. This is because the metabolites left behind by drug use are left in the blood, filtered through the blood vessels in the scalp, and remain in the hair, in detectable amounts, for about 90 days.5 Although not a popular form of drug screening due to the relatively high price tag, hair drug testing can act as a backup to urine testing in certain situations and is the only form of drug testing that can detect some substances for months after use. The substances that can be detected on a hair drug test include amphetamines, opiates, cocaine, marijuana, phencyclidine, barbiturates, and expanded opiates (oxycodone, oxymorphone, hydrocodone, hydromorphone).

Why Drug Test?

In 2015, the National Council on Alcoholism and Drug Dependence (NCADD) found that around 70% of an estimated 14.8 million illicit drug users nationwide are employed6, and the National Safety Council (NSC) reports that about 9% of all employees suffer from an actual substance abuse disorder.7 With the high costs associated with employee drug use – up to $81 billion lost annually on health care, injury treatment, turnover, absenteeism, and even theft – it pays to detect and deter drug use through employee drug testing.8

Not only that, but as an employer, you play a major role in keeping your workplace safe for your employees, and drug testing is one of the most effective ways to do so.

If you’re an employer looking to take the next steps in protecting your workplace through employment drug screens, consider the complete range of drug testing services and products available at Concentra®. Whether you are looking for pre-employment drug screens, recent-use drug testing, DOT drug testing, or another drug testing solution, we can help you better understand which options are most suitable for your organization. Take action against workplace substance use with employee drug testing by calling to speak with a Concentra expert today.


  1. Maurer, Roy. Hair, Saliva or Urine—Which Is Best for Drug-Testing Job Candidates? Society for Human Resource Management. February 15, 2018.
  2. Drug Testing FAQs. Drugs.com. Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on April 17, 2022.
  3. Villines, Zara. How long can you detect cannabis (marijuana) in the body? Medical News Today. Last updated March 3, 2023.
  4. Drug Test. Cleveland Clinic. Last reviewed August 5, 2022.
  5. Wagener, Dan. How Long Does Marijuana (Weed) Stay in Your System? American Addiction Centers. Last reviewed September 13, 2022.
  6. Drugs and Alcohol in the Workplace. National Council on Alcoholism and Drug Dependence. Last modified April 26, 2015.
  7. NSC Statement on DHHS Survey on Substance Abuse and Mental Health. National Safety Council (NSC). January 10, 2023.
  8. Working on addiction in the workplace. Harvard Health Blog. June 30, 2017.