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What is Drug Screening?

Mary McMahon
Mary McMahon
Mary McMahon
Mary McMahon

Drug screening is a test in which a tissue or fluid sample is analyzed to look for the presence of drugs. A number of drugs can be looked for in the sample, including illegal drugs as well as prescription drugs which are sometimes abused. This testing may be required for certain types of jobs, with people clearing a drug test when they start employment and are being subjected to random testing periodically. Refusal to undergo drug screening can mean denial of employment for job applications, and can result in suspension or termination for people already employed.

In addition to being used in the workplace, at both government and civilian jobs, drug screening is also used in a medical context. Hospitals may take a sample from a patient believed to be under the influence of drugs, or a patient who could be endangered by taking drugs and not informing hospital personnel. In this case, the test is performed because information about drug use could be relevant to medical treatment. Drug screening is also routinely performed as a part of some autopsies, in which case the technicians also look for traces of toxins and other unusual substances which might shed light on a death.

Many drug tests are performed on a patient's urine.
Many drug tests are performed on a patient's urine.

Oral swabs, blood, urine, and hair are all used for drug screening. The test can screen for the presence of drugs as well as their metabolites. Some labs will confirm positive results with the use of mass spectrometry, as false positives do happen, and taking the time to confirm can prevent confusion. The test results will indicate either that the blood contains no traces of drugs, or that traces have been detected, in which case the drugs will be identified.

A blood sample can be used in a drug screening.
A blood sample can be used in a drug screening.

It can take varying amounts of time for different drugs to show up in the body as they are metabolized. Drugs tend to show up in oral swabs most quickly, and linger in hair the longest. Urine tends to be used most frequently for drug testing, because it shows signs of recent drug use. Care must be taken when collecting samples to ensure that they are not contaminated. One problem with urine is that it is possible for the subject of the test to tamper with it, while something like a blood sample is harder to alter.

Oral swabs can be part of a drug screening.
Oral swabs can be part of a drug screening.

Several companies make drug screening kits which people can use to collect samples at home and send the samples in to a lab. These kits are often marketed at parents who are concerned that their children might be using drugs. Such kits are also sometimes used by workplaces that do not want to contract with a local lab.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a WiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a WiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...

Discussion Comments

Phaedrus

I applied for a job at a temporary service and the receptionist handed me a plastic cup and pointed towards the restrooms. I thought someone was supposed to watch people the entire time, but apparently not. I wasn't too worried about the drug screening test, since I didn't use drugs. I'd heard stories about false positives caused by eating poppyseed muffins or having a medical condition, though.

Now that I have a permanent job, I only have to agree to a random drug test screening. It hasn't happened to me yet. I've heard that my company will pay for the cost of drug rehabilitation if an employee does test positive for certain drugs. They don't want to lose an experienced worker if they can help it.

Reminiscence

Our company started a drug screening program a few years ago, after one of the plant employees showed up for work under the influence and caused a bad accident on the production line. He tested positive for marijuana and alcohol, and the boss decided he couldn't risk exposing the company to more accidents caused by impaired judgment. We all had to agree to employee drug screening, even the white collar workers who just worked with computers and copying machines.

I wasn't sure how I felt about taking a mandatory drug screening test, even though I did not use any illegal drugs myself. It felt a little invasive, since I didn't think an employee should lose his or her job because of a few bad habits. But I did the urine drug screening and the results were clean. One of my co-workers tested positive for marijuana, however, and she was told if she tested positive again she would be terminated.

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    • Many drug tests are performed on a patient's urine.
      By: jcreaxion
      Many drug tests are performed on a patient's urine.
    • A blood sample can be used in a drug screening.
      By: Alexander Gospodinov
      A blood sample can be used in a drug screening.
    • Oral swabs can be part of a drug screening.
      By: Gorilla
      Oral swabs can be part of a drug screening.
    • Prescription drugs can show up in a drug screening.
      By: Feng Yu
      Prescription drugs can show up in a drug screening.
    • Screening tests for the presence of illegal or prescription drugs in the body.
      By: candy1812
      Screening tests for the presence of illegal or prescription drugs in the body.