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Everything You Need to Know About Drug Testing

Drug tests are most commonly used to screen for opioids, amphetamines, cannabis, cocaine, benzodiazepines, barbiturates, and alcohol—but can be expanded by special order to include a whole host of other substances.

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If you’re going to take a drug test in the future, it’s a good idea to be informed. Here are the most common types of drug tests out there, how they work, and what you can expect when asked to take one.

If you’re involved in treatment for a substance use disorder, chances are good that you’ll be asked to take a drug test. Probably more than once. In fact, even if you don’t have a use disorder, you’re likely to take at least one test during your life, maybe as part of a job interview or health screening. Drug tests are used for everything from determining if a driver involved in an accident was intoxicated, to whether or not a mental health patient is taking her prescriptions. Now, I won’t go into my personal thoughts about the act of surveilling people’s drug use through drug screens… but I will say that if you are expecting to take a test in the future, it’s a good idea to be informed. So to that end, I am going to cover a few of the most common types of tests you are likely to come across, how they work, and what you can expect when asked to take one.

Drug tests are most commonly used to screen for opioids, amphetamines, cannabis, cocaine, benzodiazepines, barbiturates, and alcohol—but can be expanded by special order to include a whole host of other substances. Synthetic opioids like methadone and buprenorphine typically require a specialized test, for example.

Read more: Yes, Suboxone might show up on a drug test.


The two most common drug tests you’re likely to encounter as part of a drug treatment program or employment application are urine and oral fluid tests. Yes, that means pee and spit. Urinalysis tests are so common that their acronym, UA, is part of the common recovery lingo. If you’re in drug treatment now, you’ve probably already taken your fair share of UAs.

Urinalysis testing got its start during President Nixon’s “War on Drugs.” Initially used to test returning Vietnam vets for substances like marijuana and heroin, it quickly spread into civilian use as part of regular employment applications and methadone treatment programs. Now, UAs are practically synonymous with drug treatment—though a small but growing number of harm-reduction oriented treatment providers are trying to step away from the practice. One of the most humiliating aspects of urine testing is that many treatment providers find it necessary to observe the drop. Which means they watch you pee. This is supposed to deter the use of fake urine or other adulterants that can allegedly mask the presence of drug metabolites. For many of us, however, it feels like just one more form of mandatory humiliation during the lifecycle of addiction.

Lab Vs Rapid Urinalysis

If you’re being asked to take a urine test, you’ll either be taking a rapid-results test—which can be administered by a layperson and will deliver your results within minutes—or a laboratory test. Lab tests typically consist of two different types of readings, the first of which is virtually the same as the on-site test your employer or treatment provider might read in front of you: immunoassay. Immunoassay tests use antibodies to detect the presence of drugs. They deliver fast results, but can be prone to false positives, and are not able to detect specific drug levels. Basically, they can detect an initial drug positive—but further testing is needed to ensure accuracy of these results. For this reason, they are commonly referred to as screening tests. If nothing is detected during the screening, no further testing is required.

When urine is being tested in a lab, however, a positive immunoassay test will trigger a more complex type of testing, knowing as gas chromatography-mass spectrometry (GC-MS). GC-MS testing, often called confirmatory testing, is used to ensure the validity of the initial positive. This test can differentiate between different drug types within a larger category (heroin versus oxycodone, for example), and will provide drug metabolite concentration levels—which can potentially be used to determine, in a general sense, how much of a drug was used or how recently. Detection cut-offs vary. For government personnel, the opiate cut-offs are higher than those set by some civilian testing facilities; this is because poppy seeds are capable of triggering a morphine positive, so the detection levels for government personnel are set at a level which should, under normal circumstances, be unable to pick up the metabolites from poppy seeds.

How Much Urine is Needed for a Drug Test?

In terms of detection times, urine tests tend to detect metabolites longer than other tests designed to confirm short-term use. Actual detection times vary widely by substance and individual metabolism, but range between one to 30 days (and potentially even longer for drugs with very long half-lives). Because it takes a few hours for a drug to metabolize into urine, this type of testing typically cannot detect the presence of a substance that was just consumed.

Oral Fluid

Oral fluid tests use saliva to detect the parent drug as well as the presence of drug metabolites. Like urine tests, these can be performed onsite, or sent to a lab for more detailed analysis. These types of tests are advantageous for employee drug screens, in which test administrators may wish to cut down on the intrusiveness of the testing type. Afterall, it’s much less invasive to swab someone’s cheek than to watch them pee in a cup. These tests detect the presence of drugs for shorter lengths of time then urine tests, but can also detect them much sooner. Currently, oral fluid testing is not federally regulated—meaning it can’t be used for federal workplace testing—but that may change in the future.


Blood tests have one of the fastest detection windows—but also the smallest, since these tests detect parent drugs only. A blood test is a highly accurate measure of drug use when taken within the detection window, but they remain little utilized. This is probably because these tests are extremely invasive, relatively difficult procedures that requires a trained specialist to perform. Blood samples are typically taken intravenously, but sometimes with a fingerstick, depending on how much blood is required. Most substances stop being detectable by blood within 24-48 hours, which means this type of test is best used for determining extremely recent substance use.


Unlike the three testing methods detailed above, hair testing is not used to detect short-term or intermediate use. Instead, hair tests are meant to detect chronic use over a period of up to 90 days. Sometimes these tests are referred to as “hair follicle” tests, but thi
s is a misnomer. The sample is cut from the base of the head—not pulled up from the scalp, and the actual test is applied to the inner hair cortex, not the end follicle or outer hair shaft. For this reason, it’s very difficult to cheat a hair test using hair dyes or special shampoos—though there are certainly companies that will claim to have these powers!

This type of test is relatively non-invasive; the test administrator simply clips a lock of hair that is at least an inch and a half in length. As long as there’s enough of it, hair samples can come from any part of the body, not just the head. So keeping your hair cropped short won’t exempt you from a test, and could lead to a much more invasive (and awkward) ask.

Hair tests measure drug metabolites, and can show substance use as far back as 90 days, which is about three months. Cut-offs vary, but typically speaking, these tests are not designed to pick up on very infrequent use. Instead, they are meant to detect chronic or repeated drug/alcohol use.  They are often used in court settings, such as child welfare determinations. Despite some tragic outcomes caused by lab errors, hair testing is considered highly accurate and virtually uncheatable. One very serious criticism of these tests, however, is that coarse, dark-colored hair, like that often found in black and indigenous populations, might store some drug metabolites in higher concentrations than thinner, lighter hair, leaving people of color at an unfair disadvantage in comparison to their Caucasian peers.

Elizabeth Brico is a freelance writer with an MFA in Writing & Poetics from Naropa University. She is a journalism fellow with TalkPoverty and a recipient of the 2021/22 Unicorn Fund. She is also a regular contributing writer for HealthyPlace’s trauma blog. Her work has appeared on Vice, Vox, Stat News, The Fix, and others. When she isn’t working, she can usually be found reading, writing, or watching speculative fiction.

Any general advice posted on our blog, website, or app is for informational purposes only and is not intended to replace or substitute for any medical or other advice. Workit Health, Inc. and its affiliated professional entities make no representations or warranties and expressly disclaim any and all liability concerning any treatment, action by, or effect on any person following the general information offered or provided within or through the blog, website, or app. If you have specific concerns or a situation arises in which you require medical advice, you should consult with an appropriately trained and qualified medical services provider.

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