As substance use disorder continues to be a major public health issue, drug testing has become a standard practice for purposes ranging from pre-employment screening to court-ordered monitoring. Here’s a look at how drug tests work and what you can expect if you need to take one.
What exactly is a drug test?
A drug test checks for the presence of drugs and their metabolites in your system. Metabolites are the substances left behind after the body breaks down drugs. The most common sample types used for drug tests are urine, blood, hair and saliva.
After you provide a drug test sample, it is sent to a lab for analysis. Initial drug screenings are performed using a method called immunoassay, which is a test that uses antibodies to detect the presence of drugs and their metabolites. While this screening doesn’t measure how much of a drug was used, it can indicate the presence or absence of drugs in the system. If screening indicates a presumptive positive for that drug, a second confirmation test is performed to confirm the positive results and provide the most accurate result.
What sample types are used for drug testing?
Drugs and their metabolites get stored in the body in different ways. For example, marijuana metabolites get stored in fat cells and are slowly released over time into urine. Other drugs like cocaine can be detected in urine for only a few days after use. Hair testing can detect drug use over a longer time, since trace amounts in the bloodstream get deposited into growing hair strands.
Some of the most common sample types used for drug testing include:
- Urine: The most frequently used sample type. A urine drug test can detect recent drug use. The test requires providing a urine sample into a collection cup
- Blood: Not as common as urine tests but can detect very recent drug use. The test requires having blood drawn by a medical professional
- Hair: Used to detect longer-term drug use. The test requires snipping a small hair sample near the scalp
- Saliva: Checks for very recent drug use. The test requires swabbing of the inside of the mouth
What drugs are included in drug test panels?
Many drug tests use a six-panel or expanded 11-panel test to check for multiple commonly used drugs. Certain drugs can stay in your system longer than others, so if you’re checking for the presence of a specific drug, it’s important to know how long that drug is detectable in your system.
A six-panel drug test typically tests for the drugs listed below. The times listed in parentheses indicate how long the drug metabolites may be detectable in urine.
- Amphetamines like speed and methamphetamine (up to 2 days)
- Cannabinoids like marijuana or THC (2-7 days for single use, 1-2 months for chronic use)
- Cocaine (up to 4 days)
- Opiates like morphine, hydrocodone or codeine (2-7 days depending on the opiate)
- Oxycodone (1-4 days)
- Phencyclidine or PCP (14 days for single use, up to 30 days for chronic use)
An expanded 11-panel adds tests for:
- Barbiturates (2 days to 3 weeks)
- Benzodiazepines like alprazolam or diazepam (up to 6 weeks)
- Fentanyl (1-3 days)
- MDMA or ecstasy (up to 2 days)
- Methadone (about 3 days)
Preparing for and taking a drug test
There is no standard preparation for a drug test other than having a form of identification with you and being ready to provide a sample. However, it is recommended that you inform your testing professional of any over-the-counter medications or supplements you may be taking, as they may affect your test results. Avoiding foods with poppy seeds is also recommended, as they can be detected as a false positive for opiates in a drug test.
Results are usually available within 1-5 days. A positive result means the drug or metabolite was detected in your system. A negative result means drugs weren’t detected but does not mean there are no drugs present in your system. Following up with a healthcare professional is the best way to confirm your results.
Test your drug exposure with Labcorp OnDemand
Labcorp OnDemand offers multiple options for someone seeking drug testing for personal use or peace of mind. Our Standard Drug Test checks for six common drugs of abuse, and our Complete Drug Test is an expanded 11-panel test. Both require urine samples that must be collected in person at a Labcorp patient service center.
Convenient and reliable drug testing services can give you the insights you need into your drug exposure.
