There are various tests that can be performed to determine whether someone has used drugs recently. You’re probably familiar with urine tests that indicate this information. However, this type of test typically only shows if drugs have been used within a short period of time before the test. That’s why many employers are choosing to have potential and existing employees drug tested using their hair instead of urine. This is called a hair follicle drug test.
What is a Hair Follicle Drug Test?
A hair follicle drug test screens for the misuse of prescription medication and illicit drug use. The test involves a small number of hair strands being cut from your head close to the scalp. Then, your hair sample is tested by a lab to determine if there has been any drug use for the last 90 days.
How It Works, Uses, and What to Expect
In a hair follicle drug test, the sample hair is used, usually from the root or close to it, to screen for drug use. When you use drugs, they are absorbed into the bloodstream. Within each hair follicle, there is a blood vessel that feeds hair growth cells. If you have used any substances, those drugs are carried into the hair follicle via the blood vessel. Traces of the substances can then be detected in the hair follicle, which is why it’s called a hair follicle drug test.
Hair follicle drug tests can screen for various types of drugs, both prescription and illegal. Some of the drugs tested for include:
- Marijuana
- Cocaine
- Amphetamines
- Methamphetamines
- PCP
- Ecstasy
- Opioids (prescription painkillers and heroin)
When you go to have a hair follicle drug test, the hair sample that is taken must be directly from your head. You cannot use hair from a brush or other sources. The sample has to include enough strands to equal about the thickness of a pencil, and it needs to be at least one and a half inches long. Despite the name of the test, the hair doesn’t have to be pulled to include the root, but it must be cut as close to the scalp as possible.
Usually, hair drug tests take place in a lab or other medical setting. Some workplaces may cut the hair themselves and send it in to a laboratory using a kit. Additionally, hair testing kits can be purchased online for at-home use.
If a clean drug screen is required for hire, or your employer has mandated that you have a test, you will likely have to have it done in a supervised facility. This ensures that the hair that is taken does, in fact, belong to you.
Once your identity is confirmed, the lab technician or other personnel will cut about 100-120 strands of hair from the crown of your head. They may collect hair from other areas, or multiple areas, so they do not leave a bald spot. If you have very short hair, or are bald, the lab technician may take hair from other parts of your body instead. The hair is then placed in foil, then in a security envelope, and it is sent for the testing.
Whether you wash your hair, dye or bleach it, or use styling products, it will not affect the hair follicle drug test’s accuracy. It will show any drug use within the last five to 90 days.
Hair Follicle Drug Test Cutoff Levels
Hair follicle drug testing uses cutoff levels to indicate whether a test is negative or positive for the presence of specific drugs. In employment drug testing, there is an industry standard that involves a two-tier testing method. That means that there is an initial screening on one part of the hair specimen, then another test, or confirmation test, on another part of the original sample.
The first test is used to separate negative samples from any further testing. The second, more thorough testing uses more definitive processes, including chromatography-mass spectrometry, to identify and measure specific drugs in the sample. It’s essential that cutoff levels are selected based on the substance tested for, to comply with regulation standards. It’s only if a substance is identified at concentration levels that are equal to or greater than the cutoff, that it will be reported as a positive result by the lab. That means that a negative test doesn’t necessarily mean that there wasn’t a drug indicated, it just means that if there was, it was in an amount lower than the cutoff level and therefore, couldn’t be reported.
The cutoff levels for hair follicle testing are stated in picograms (PG) per milligram (MG). Cutoff levels for the most commonly hair follicle drug tested substances are as follows:
| Drug | Screen Cutoff Level | Confirmation Cutoff Level |
| Marijuana | 1 pg/mg | 0.1 pg/mg |
| Amphetamines/Methamphetamines | 300 pg/mg | 300 pg/mg |
| Cocaine | 300 pg/mg | 300 pg/mg |
| Opiates | 500 pg/mg | 500 pg/mg |
| PCP (phencyclidine) | 300 pg/mg | 300 pg/mg |
How Can You Pass a Hair Follicle Drug Test?
There is only one sure way to pass a hair follicle drug test, and that is to not use any drugs for the 90 days before you take the test. This type of drug test, unlike urine tests, is nearly impossible to cheat because the person who takes the hair sample does so directly from your head and they are well-trained to collect it.
Obviously, if you rid your entire head and body of any hair, the test cannot be performed. However, that may very well mean the same as a negative test to some employers. There are special hair products out there that advertise they will make your hair drug test come back negative, but don’t be fooled by them – they don’t work.
In the event that your hair follicle drug test comes back positive, you may be tempted to admit that you had been around drugs, like second-hand marijuana smoke, but that you yourself had not used them. This excuse won’t work because the hair follicle drug test screens for the drug and the metabolites your body produces. The test will only come back positive if you smoked or ingested the drug yourself. In other words, if your hair was exposed to marijuana, but you did not smoke or ingest it, your test would come back negative.
Final Thoughts
Many employers use the hair follicle drug test for prospective employees or randomly for existing employees. These tests can detect drug use up to three months prior to the test. The only way to ensure that you don’t have a positive test is to not use any substances that will be tested for within 90 days of having the hair drug test done. These tests are very accurate, and they provide employers with valid information about the individuals working for them.
If you are required to have a hair drug test, be sure to let the lab technician know if you are taking any prescription medication. There are some medications that can result in a false-positive result.
