Hair Drug Test: Everything You Need to Know


Hair follicle tests, commonly known as hair drug tests, screen for illegal drug use and abuse of prescribed medications. During the process, a small quantity of hair is taken from the head and analyzed to identify signs of illicit drug usage during 90 days prior to the test.

Generally, it’s done to test for:

  • Marijuana
  • Ecstasy
  • Methamphetamine
  • Amphetamine
  • PCP
  • Cocaine
  • Opioids (morphine, 6-acetylmorphine, codeine)

Your workplace could request a hair drug test randomly or upon notice to screen for illegal drug use. So, learning some facts regarding the test will come in handy.

What Happens Behind the Scene

A hair drug test usually takes place in a hospital or a laboratory. Sometimes, workplaces perform the drug test themselves using a special kit, which is then mailed to the lab.

If you’re asked to take the drug test by your company, it’s possible that you’ll be supervised in the course of the entire process.

You could wash or dye your hair without affecting its accuracy.

After authenticating identifying information, they will remove between 100 to 120 hairs from your head. To avoid leaving a bald area, they might collect hair from different parts on your head.

The collect may also use your body hair to perform the test, depending on whether you’re bald or have less hair. Your hair is then carefully placed in foil and mailed overnight for testing.

About the Results…

Negative results are usually identified within a day of your hair removal. Here, a test known as ELISA conveys the screening test. It detects whether or not the sample provided is negative for illicit drug use. If the result is negative, it essentially means you haven’t used any drugs over the last 3 months.

Positive hair follicle tests are confirmed after 3 days. All non-negative tests go through a second testing procedure known as gas chromatography-mass spectrometry (GC-MS), which confirmes a test result is positive. It also detects what drugs were used specifically.

Inconclusive results aren’t very common, especially when each testing procedure is followed adequately. Sometimes, improper hair collection can cause an error, in which case the test is repeated.

And finally, the lab responsible for drug testing delivers the result to the organization or individual requesting the hair drug test. To make sure your results come out negative, read this review on how to get weed out of your system effectively.

About the Accuracy…

Hair collection and the testing itself follow a few specific standards to enhance accuracy. During the testing process, the hair is tested for possible environmental contamination, which could change your test results.

To prevent false-positive results, two tests are usually conducted. ELISA, as mentioned earlier, can deliver a positive or negative result within a day. On the other hand, GC/MS is the widely preferred method for verifying positive results. It can detect up to 17 different drugs, according to ResearchGate.

Certain medications could influence your test results. For example, if you were prescribed opioid painkillers, they will appear on your result. In this particular case, you’ll be asked to provide the doctor’s documentation and prescription.

Don’t forget to ask for a retest if the results seem inaccurate.

About the Cost…

Compared to a urine test, hair follicle drug tests are more expansive. It would require between $60-$80 to buy an at-home kit, while tests performed in a lab or hospital will cost somewhere between $100-$150.

If your workplace conducts a surprise hair drug test, note that they are required by law to pay you for not only the test but also the hours spent taking it.

If the test is part of your pre-employment screening, note that the employer won’t pay a dime for your time.

That said, some insurance carriers may cover your drug test expenses— if performed in a hospital for medical purposes.

Wrapping Up

As you can see, a hair drug test can detect the use of drugs for up to 3 months preceding the test because the substances in your bloodstream end up becoming part of the hair cells as your hair grows.

These tests aren’t best suited for identifying the recent use of illicit drugs, as it could take up to 7 days for the drug to be detectable via the hair follicle test.

If you are currently taking any prescribed medications, make sure your employer or the drug test conductor knows about it. Medications can often lead to false-positive test results.

Let us know in the comments below if you have any thoughts or suggestions regarding hair follicle drug tests.