All You Need to Know About Hair Drug Testing

Hair follicle drug testing is one of the most convenient methods to detect drug abuse. It is now gaining popularity among employers who conduct random on-site drug testing at the workplace or pre-employment screening. It is also preferred by parents who want to test their kids for drug use.

Court systems in several countries such as the United States, United Kingdom, and Canada also recognize the evidentiary weight of hair drug testing results. In the U.S., results from hair follicle analyses are legally and scientifically recognized under several established Rules of Evidence.

What is Hair Drug Testing?

Hair drug testing is a method used to determine whether the person being tested has a history of drug use. It typically requires at least 100 strands of hair that are cut at the scalp. According to research, drug metabolites that run in the bloodstream are absorbed by the hair as it grows. Because long-term drug use produces metabolites or by-products that are absorbed into the blood and stored in the hair, this screening method allows for a longer detection window compared to other tests. It can detect drug use for up to 90 days from the last exposure, depending on the substance being tested.

What drugs are tested in a hair follicle test?

Hair screens can identify a number of substances. Some of the most common substances are as follows:

Amphetamine (AMP)
Cocaine (COC)
Ecstacy (MDMA)
Marijuana (THC)
Methamphetamine (mAMP)
Opiates (OPI)
Phencyclidine (PCP)

There are many types of hair drug tests to choose from. Some follicle drug tests can detect prescription drugs:

Vicodin (Hydrocodone)
Lorcet/Lortab (Hydrocodone)
Oxycontin (Oxycodone)
Percocet/Percodan (Oxycodone)
Dilaudid (Hydromorphone)

How Hair Drug Test Works

1. Measure Sample

Typically, more than 100 hair strands are necessary to perform a hair drug test properly. This much is needed because hair growth is not consistent. Amounts fewer than this may not produce accurate results.

2. Collect Hair

Collect a hair sample (about the thickness of a pencil) from the donor. Cut hair as close to the scalp (root) as possible. Hair specimen can come from other areas of the body if head hair is not at least 1.5 inches in length.

3. Send Sample to Laboratory

Sent hair sample to the nearest laboratory using the prepaid shipping label included in the hair drug test. A certified technician will process the hair sample to identify any drug metabolites. The hair is washed to remove secondhand/external contamination, where it later undergoes an initial screening process called Enzyme Immunoassay (EIA) technology.

4. Confirmation of Results

If the sample tests positive, it undergoes a confirmation test using highly accurate chromatographic techniques to verify the presence of drug metabolites. These procedures include GC/MS (Gas Chromatography-Mass Spectrometry) and LC/MS (Liquid Chromatography-Mass Spectrometry).

5. Obtain Results Online

If the initial screening and confirmation tests both return positive results, the hair test is reported to be positive. Samples that yield a negative result during the initial screening are discarded and reported as negative.

Frequently Asked Questions about Hair Drug Testing

1. How long does a hair follicle test go back?

Drug testing with hair can detect drug metabolites up to 90 days after abuse. Every half inch of hair corresponds to a drug abuse history of approximately 30 days. To properly conduct a hair test, a minimum sample submission size of 0.5 inches is required, up to a maximum of 1.5 inches. It is also important to obtain the hair sample as close to the scalp as possible to provide the most recent results.

2. Do hair drug test detection times vary depending on when drugs are used?

It takes about 4-5 days after drugs are abused before hair grows beyond the scalp containing metabolites. Body hair growth rates are generally slower and therefore should not be submitted to determine a history of substance abuse if drug abuse occurred within one business week.

3. How much hair is needed for a drug test?

A standard hair follicle drug test with Gas Chromatography/Mass Spectrometry (GC/MS) confirmation requires a minimum of 60 milligrams of hair, or approximately 90 to 120 strands depending on hair thickness. For visual reference, the strand sample should be the diameter of a pencil.

4. Can drug tests be run on people with little or no hair?

Yes. As long as hair collected from the head meets the minimum hair sample length of 1.5 inches, accuracy will not be compromised when drug testing with hair. If head hair is too short, body hair can be used as a substitute. Since body hair requires more time to grow than head hair, the hair drug test detection window may be extended. Best results are obtained if the submitted hair follicle sample is collected from only one source. Hair follicle samples from the scalp should not be combined with hair from other areas of the body.

5. Is it possible to drug test body hair with a HairConfirm™ Hair Follicle Drug Test kit?

Yes, body hair can be used for hair drug testing and provide the same accuracy as a head hair submission. Since body hair is replaced less often than head hair, the detection window of a hair test kit can extend up to one year.

6. Can I submit hair from a hairbrush for hair drug testing?

It is not recommended to submit a hair sample from a hairbrush, shower drain, or any source apart from the scalp. Hair samples collected from external sources may be combined with other people’s hair, which would inevitably affect hair test accuracy. If the donor’s identity is vague or inconclusive because of a mixed hair sample, the laboratory will reject the test.

7. How long does a hair follicle test take?

Drug testing with hair follicles differs from other drug testing methods because laboratory confirmation is required to provide the most reliable results. All HairConfirm™ kits include a free prepaid shipping label addressed to our certified HairConfirm™ laboratory, while HairConfirm™ Express offers an expedited overnight prepaid shipping label. Confidential results are delivered 2-3 business days after reception of a hair sample.

8. Can a hair drug test detect one-time use?

It is unlikely for a hair test to detect one-time drug use. Hair drug tests are a good solution to screen occasional or frequent substance abuse, as recurrent drug use will more likely meet a hair test's minimum drug concentration cutoff levels.

9. how to read hair follicle test results?

Hair drug test results will indicate a positive or negative result for each drug class on a confidential lab report. If a hair sample tests positive, the results section of the drug test report will quantify the amount found in the sample with the cutoff level of the test.

10. Does hair color affect drug test results?

Hair color is a genetic trait determined by the amount of melanin pigment in hair. It has been shown experimentally using real hair samples that hair color has no effect on the outcome of a follicle drug test. Hair samples are scrubbed beyond the strand's shaft where pigment is held, so not even hair dye will compromise hair follicle drug test accuracy.

11. Will passive exposure to drugs affect hair test results?

Drug testing with hair follicles can discern between parent drugs and metabolites to rule out the possibility of environmental drug exposure. Finding traces of parent drugs is not enough evidence to suggest drug abuse, whereas the presence of liver-produced metabolites indicate exposure to drugs beyond external cross-contamination.

12. Can hair be affected by cross-reactive substances like over the counter medication?

Hair drug screening uses Enzyme Immunoassay Antibodies (EIAs) to detect false positives caused by over the counter medications e.g. cough syrup or acetaminophen (Tylenol®). While cross-reactivity can occur, preliminary positive drug tests undergo Gas Chromatography/Mass Spectrometry (GC/MS) to confirm early findings. If confirmed results remain positive, they are interpreted by a Medical Review Officer (MRO) for further explanation.

13. Can you really pass a hair follicle test with bleach or detox shampoo?

Bleaching or dying of the hair will not disguise the history of drug abuse contained deep within the hair follicle. Hair drug tests are the hardest drug testing method to adulterate or cheat for this reason. In fact, it is virtually impossible to pass a hair test if drug abuse has occurred, so donors should be wary of “drug test shampoos” and similar products. The best way to pass a drug test is to simply remain sober.

14. How fast does head hair grow?

On average, head hair grows approximately 0.5 inches (1.3cm) each month. This growth rate varies slightly based on age and genetic factors, so it is recommended to provide a weeklong “grace period” before ordering a hair follicle drug test.

15. How do drugs get into hair?

After a substance is ingested, smoked, snorted, or injected, the liver is responsible for breaking drugs down to metabolites as it detoxifies the body. These metabolites circulate throughout the bloodstream, subsequently nourishing hair follicles as they grow from the scalp. The only way to remove drugs from the follicle is to cut the hair.

The Pros and Cons of Hair Drug Testing

Like all other drug testing methods, hair follicle test also has its pros and cons. Knowing the pros and cons of hair drug testing will guide employers when deciding whether or not it’s a suitable drug testing method for their workplace.

Advantages of Hair Drug Testing

Longer window of detection : Drugs are processed in the body to produce metabolites which remain in the bloodstream and are later deposited into the hair follicle. A hair drug test determines a history of drug abuse up to 90 days after intoxication.
Less risk of adulteration: There is virtually impossible to cheat a hair drug test. Hair screen results are highly accurate. Since metabolites are stored in the hair shaft, attempts to beat the test i.e. hair washing and/or applying bleach or dye will not affect results.
Easy storage: Hair specimens are easier to collect, store, and handle when compared with other drug test types. Hair is arguably more sanitary than obtaining urine or saliva.

Disadvantages of Hair Drug Testing

More expensive: Hair drug testing is slightly more expensive than urine or saliva drug tests. One reason is that it cannot be performed at home. Another is because more complex processes are involved in analyzing the samples.
Results based on sample length: According to studies, hair grows on average of 1.4 cm per month. Hence, laboratories usually use at least 1.5 cm of the hair from the root end during the testing process to assess the donor’s 90-day drug use history.
Longer waiting period: Hair analysis takes longer compared to other screening procedures since samples must be processed in a laboratory. Results become available 2 to 3 days after the sample is received.

Hair Drug Testing Products

Some home test kits allow the collection of the hair sample and provide for a package within which the specimen can be sealed. The sample is then mailed to an accredited laboratory where it undergoes testing and analyses. Some parents use these kits to screen their teens for possible drug use.

Here are a few of these home test kits:

HairConfirm 7 Panel Hair Follicle Multi-Drug Testing Kit

This test kit comes with materials that can be used for sample collection such as a collection foil, specimen pouch, and I.D. card. The HairConfirm laboratory can test for marijuana, cocaine, amphetamines, methamphetamines, opiates, ecstasy, and phencyclidine. The results are made available within two business days after receipt of the sample.

HairConfirm + Prescription Drugs 12 Panel Hair Follicle Multi-Drug Testing Kit

This product includes the same materials as the 7-Panel Hair Follicle Multi-Drug Testing Kit. What makes this product different is that aside from testing for the 7 major drugs, the hair sample can also be used to detect the presence of 5 prescription drugs (Vicodin, Lorcet, Oxycontin, Percocet, and Dilaudid). The results are also available within two days from receipt of sample.

5 Panel Laboratory Hair Drug Testing Service

This is a lab-based hair drug testing kit intended to be used for pre-employment screening. The purchaser is allowed to select his nearest testing facility and hair collection is arranged at the testing center.

The laboratory can analyze the hair sample for the presence of metabolites of drugs such as marijuana, cocaine, amphetamines, benzoylecgonine, opiates, and phencyclidine. The results are usually available within 5 to 7 business days from sample collection.