Everything You Should Know About a Hair Follicle Drug Test
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What is a hair follicle drug test?
A hair follicle drug test, also known as a hair drug test, screens for illicit drug use and the misuse of prescription medication. During this test, a small amount of hair is removed from your head using scissors. The sample is then analyzed for signs of drug use during the 90 days preceding the test. It’s typically used to test for:
- opioids (codeine, morphine, 6-acetylmorphine)
While a urine drug screen can detect if you’ve used drugs in the last few days, a hair follicle drug test can detect drug use in the past 90 days.
Your workplace may request a hair follicle test to screen for illicit drug use before hire or randomly during employment. Some research also indicates that hair drug testing can be useful for monitoring drug use in at-risk individuals when used alongside self-reporting.
Your hair follicle test might take place in a lab or within a hospital setting. Or your workplace may perform the test using a kit that’s then mailed to a laboratory. You can also order at-home hair follicle tests online.
If your workplace has mandated that you take the test, they’ll likely require you to be supervised during the testing process.
You can wash your hair, dye your hair, and use styling products without affecting the accuracy of the test.
After confirming identifying information, the collector will cut between 100 and 120 hairs from the crown of your head. They can collect the hairs from different spots on your crown to avoid creating a bald spot.
If you have very little or no hair on your head, the collector might use body hair for the test instead. The collector will place the hair in foil and then in a secure envelope to be mailed for overnight testing.
A negative result can be determined within 24 hours of hair removal. A test called ELISA is used as a screening test. This test determines if the hair sample is negative for drug use. A negative result indicates that you haven’t engaged in illicit drug use over the past 90 days. Additional testing is required to confirm a positive result.
A positive drug test is confirmed after 72 hours. All nonnegative tests undergo a second test, called gas chromatography/mass spectrometry (GC/MS). It confirms a positive test result. This test also identifies the specific drugs used.
An inconclusive result isn’t common when testing procedures are followed. In some cases, improper collection of the hair specimen may result in the test being rejected completely. In this case, the test may be repeated.
The laboratory responsible for testing will deliver the results to the individual or organization requesting the test. They’ll use confidential means, like a secure fax, a phone call, or an online interface to share test results. Because lab results are confidential health information, you’ll need to sign a release before the results are passed on to your workplace.
Can the test identify the date of drug use?
A hair drug test detects a pattern of repeated drug use over the last 90 days. Because hair growth rates vary from person to person, this test can’t accurately determine when in the 90 days drugs were used.
The collection and testing of hair for this test follows a very specific set of standards to increase accuracy. During testing, the collected hair is washed and tested for environmental contamination that could change the results of the test. Your results won’t be affected if you wash your hair, dye your hair, or use styling products.
To guard against a false positive, laboratories conduct two tests. The first, called ELISA, is able to deliver a negative or positive result within 24 hours. The second, called GC/MS, is a widely accepted method for confirming a positive result. This second test can also test for specific drugs and can detect as many as 17 different drugs. The GC/MS also guards against false-positive results caused by foods like poppy seeds or hemp seeds.
One 2017 study did find inconsistency between self-reporting of cannabis use and the results of hair drug tests. This may indicate the potential of a false positive.
Certain medications may influence the results of the test. If a doctor has prescribed an opioid painkiller and you use them as directed, these drugs will show up on your test. In this case, your employer will likely request you provide documentation of prescriptions.
If you believe your hair drug test results are inaccurate, you may immediately request a retest from your employer.
A hair follicle drug test can be used to detect drugs used over the past 90 days. A second screen is used to confirm positive test results. Some medications may result in a false positive, so be sure to share information about your prescriptions and supplement use with the screener.
How Long Does Weed (Marijuana) Stay in Your System?
It varies according to dose
Weed, also known as marijuana or cannabis, is usually detectable in bodily fluids for 1 to 30 days after last use. As with other drugs, it may be detectable in hair for several months.
Weed detection windows depend on how much you smoke or ingest, as well as how often. In general, higher doses and more frequent use are associated with longer detection times.
For daily users, cannabis may be detectable for several months after last use. The longest-reported detection times are more than 90 days.
Read on to find out the detection windows for cannabis in urine, blood, saliva, hair, and more.
Drug tests measure weed and its by-products, or metabolites. These metabolites remain in your system long after weed’s effects have worn off.
According to Mayo Clinic Proceedings, weed is detectable in urine for the following amounts of time after last use:
- Occasional users (up to three times a week): 3 days
- Moderate users (four times a week): 5 to 7 days
- Chronic users (daily): 10 to 15 days
- Chronic heavy users (multiple times a day): more than 30 days
Cannabis metabolites are fat-soluble, which means they bind to fat molecules in your body. As a result, it can take some time for them to leave your system.
According to an article in Therapeutic Drug Monitoring, weed is typically detectable in the blood for 1 to 2 days. However, in some cases, it’s been detected after 25 days. Chronic heavy use increases the length of time that it can be detected.
Weed is detectable in the bloodstream within seconds of inhalation. It’s distributed to the tissues. Some of it is reabsorbed in the blood and broken down. Its metabolites may remain in the bloodstream for days.
Blood testing may be used in laboratory settings or to indicate recent use of weed.
According to a 2014 review on cannabinoids in oral fluid, weed is detectable in saliva for the following amounts of time after last use:
- Occasional users: 1 to 3 days
- Chronic users: 1 to 29 days
Weed can enter the saliva through smoking and exposure to smoke. However, its metabolites are only present in saliva when weed has been smoked or ingested.
In jurisdictions where weed is legal, oral fluid may be used for roadside testing.
Hair follicle tests assess drug use for up to 90 days . After use, weed reaches the hair follicles via small blood vessels. Trace amounts may remain in the hair.
Since hair grows approximately 0.5 inches per month, a 1.5-inch hair segment taken close to the scalp can provide a window of weed use for the past three months.
The active ingredient in weed is a chemical substance called THC, which stands for delta-9-tetrahydrocannabinol. THC that enters your body is absorbed into the bloodstream.
Some THC is temporarily stored in organs and fatty tissues. In the kidneys, THC can be reabsorbed into the bloodstream.
THC is broken down in the liver. It has more than 80 metabolites, but the most significant ones are 11-OH-THC (11-hydroxy-delta-9-tetrahydrocannabinol) and THCCOOH (11-nor-9-carboxy-delta-9-tetrahydrocannabinol).
Drug tests look for these metabolites, which stay in your body longer than THC. Eventually, THC and its metabolites are excreted in urine and stool.
A number of factors affect how long weed stays in your system. Some of these factors, such as your age, gender, and body mass index (BMI), aren’t related to the drug itself, but to how your body processes and metabolizes the drug.
Other factors are related to weed and how you use it. This includes how much you take (dose) and how often (frequency). Higher doses and more frequent use tend to increase the amount of time it takes to eliminate weed from your system.
More potent weed, which is higher in THC, may also stay in your system for longer. Weed that’s ingested may also remain in your system slightly longer than weed that’s smoked.
There isn’t much you can do to speed up the amount of time it takes for weed to leave your system.
Once it’s entered your system, your body needs time to break it down. Exercising, eating healthy, and staying hydrated may help, but not drastically.
There are a number of weed detox remedies and kits available on the internet. Many require drinking a lot of water to dilute your urine, and then using herbal supplements such as creatinine or vitamin B-12 to mask the dilution.
These kits don’t work reliably.
Weed’s effects appear quickly, usually within 15 to 30 minutes after smoking. It can take one or two hours to feel weed’s effects when it’s ingested.
Weed’s active ingredients produce a short-term “high.” Common effects include:
- sense of well-being
- sense of relaxation
- feeling that time is slowing down
- giggling or chattiness
- altered sensory perception
Other short-term effects include:
- inability to focus
- increased appetite
- coordination problems
- rapid heart rate
- dry mouth and eyes
- feeling sick or faint
- anxiety or paranoia
In rare cases, high doses of weed can cause hallucinations, delusions, and psychosis.
Smoking or ingesting weed on a regular basis can have additional effects on your mind and body. You might be at an increased risk of developing:
- cognitive impairments
- memory impairments
- learning impairments
- cardiovascular diseases, such as heart disease and stroke
- respiratory illnesses, such as bronchitis and lung infections
- mood disorders, such as depression and anxiety
- hallucinations and psychosis
If you use weed while you’re pregnant or breastfeeding, there’s a greater chance that your baby will have birth defects or problems with brain development.
Weed’s short-term effects start to taper off after one to three hours. Some effects, like memory problems or trouble sleeping, can last a few days.
Researchers don’t know how long the effects of chronic use last. Long-term effects can last days, weeks, or months after weed use has ended. Some effects may be permanent.
Weed may stay in your system anywhere from several days to several months after last use. Detection windows depend on the drug test used and other factors, such as whether you smoke or ingest weed on a regular basis.
Weed is detectable in bodily fluids for up to 30 days after last use. For daily users, weed may be detectable for several months after last use. The longest-reported detection times are more than 90 days. Here’s how long it’s detectable via each type of drug test, whether you can metabolize it faster, and more.