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Hair Drug Tests

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A hair follicle drug test is a forensic toxicology test that identifies if someone has ingested drugs in the past 5 to 90 days. The hair test detection period is far greater than a urine test, which typically detects drug and alcohol use for about a week. Hair tests should be used to identify repeated, chronic, or binge usage over an extended time frame. Hair testing is a newer methodology, but is becoming more and more popular among employers and court systems, due to the extensive look-back period that it offers. If a person does not have enough head hair, then body hair may be used for this test.

Health Street conducts a variety of hair drug test panels at over 5,000 locations nationwide. Choose a hair test and pick a clinic online.

What is a Hair Follicle Drug Test?

When someone ingests drugs, the drugs enter the bloodstream. Simultaneously, the body metabolizes those drugs, and the resulting metabolites also circulate through the blood. Because the blood nourishes the hair follicles, the consumed drugs and their metabolites get deposited into the hair follicle. When the hair grows out of the follicle, the evidence of drug use remains intact, where it remains indefinitely.

Despite the name of this test, we do not actually test the follicle (or “root”) itself. In fact, we test the first inch and a half of hair growth from the base, equating to an approximate 90 day history of drug use. If the head hair is less than an inch and a half, we can test body hair. There is some debate about the look-back period for body hair. Our lab estimates it at 90 to 365 days.

Pros and Cons of Hair Drug Tests


Longer look back than urine test (up to 90 days or more)
Very difficult to cheat (we cut the hair right from the person’s head or body)
Less mess than a urine test


If person has no head or body hair, then the test can’t be done
Bleached hair is a less stable reservoir of drug metabolites than untreated hair
The look back period on body hair can vary from person to person. For example, some studies show darker hair retains drugs better than lighter hair

Are Hair Follicle Drug Tests effective?

Hair tests are extremely effective at identifying repetitive drug use over an extended period of time in persons with enough hair to test. It is nearly impossible to cheat a hair drug screening. Our technicians cut the hair directly from the head of the person being tested. Furthermore, shampoos do not work to change the hair’s ability to retain evidence of drug use.

On the other hand, bleached hair, while it doesn’t automatically disqualify someone from taking a hair test, is less stable for retaining drugs. And, incidental usage (such as one time in the past 90 days) tends not to get picked up in a hair screening. Finally, if a person used drugs in the immediate past (the most recent 5 days), it will not have had time to grow out of the hair follicle into the strand of hair that we cut and test.

How Does Hair Testing Work

A small amount of hair (approximately 120 strands) are cut and sent to our lab for analysis. We need at least 1.5 inches of hair to do this test, and we can use hair from the head, chest, leg, or armpit. Some of our clinics only perform the head hair test, while others do body hair as well. The hair is cut by one of our technicians at a clinic; you should not bring pre-cut hair with you.

Second Hand Smoke

Environmental exposure (such as second hand marijuana smoke) does not cause a positive hair test. We test for both the drug itself as well as the metabolites that your body generates when you inhale the smoke. Even if the smoke somehow got lodged in your hair, if you didn’t inhale it, your hair will have no evidence of the metabolites.

How long do Hair Follicle Screenings take for results?

After the hair specimen is provided, it is delivered to one of our certified laboratories for professional analysis. Basic tests, such as the 5 panel, typically come back in 2-3 business days when negative. The more complex 9, 12, or 14 panel tests – and hair alcohol tests – take longer (3-5 business days). Finally, non-negative screens are subject to confirmation testing, which adds a few days onto the processing time.

What drugs can be detected in a Hair Test?

Hair tests can detect nearly all of the most common street and prescription drugs. The drugs included in a given hair follicle test range from 5 to 17 panels, including some specialized panels that include testing for alcohol consumption.

Why use Health Street for Hair Drug Testing?

Hair testing is still a relatively new technology. Though it is easy to administer by properly trained technicians, many drug testing companies have little experience with it. Therefore, it is important to use a company that performs hair testing daily. Health Street is a leader in hair drug panels, and has developed expertise to help make the testing process as efficient and frictionless as possible. All hair samples go to certified laboratories for examination. If the initial screening is non-negative, all of our tests include GC/MS (gas chromatography/mass spectrometry) confirmation testing.

Health Street’s hair follicle drug tests are always reviewed by one of our certified Medical Review Officers (MROs) prior to the release of results, which allows people who are taking prescribed medication a chance to prove those medications to our doctors. Legally prescribed medications that are taken consistent with the prescribed dosage will be listed as “negative” on the final report.

You are encouraged to discuss your drug screening requirements with one of our professional representatives. We can assist you in the development, design and implementation of a hair follicle drug testing program that will meet your company, personal, or court-related objectives. Just call (888) 378-2499 for assistance.