Introduction
A hair follicle drug test can identify patterns of prescription drug abuse or illegal drug usage over a set period, usually three months, in the case of head hair samples. A single hair sample can be tested for many substances or drug classes, or a hair follicle test can be used to check for a specific drug. For example, a test on hair follicles can identify the following:
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Opiates such as heroin, Codeine, and Morphine.
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Phencyclidine.
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Amphetamines, including Methamphetamine, MDMA (ecstasy), and MDEA (eve).
In addition to the more conventional urine-based testing, specific business, legal, medical, and educational institutions are now using hair follicle tests for drug testing. Drug metabolites can remain in scalp hair for up to three months, which has increased interest in hair follicle testing. Hair follicle testing requires a process that can last up to two steps to lower the possibility of false positive results.
People taking prescription medicine should let their employer or the test administrator know. Some prescription drugs can be detected by hair follicle tests, which could result in a false-positive result.
Why Is Hair Follicle Drug Test Necessary?
Drug tests could be required of a person for professional, legal, or medical reasons. Some employers, especially for positions with a high risk of damage, ask prospective employees to submit to a drug test as part of the recruitment process. Additionally, employers can conduct random drug tests on present workers or request such tests in response to serious mishaps or incidents.
Drug testing regulations in the United States differ from state to state. For example, some states forbid companies from randomly testing their workforce for drugs. In these states, an employer must justify why they chose to try a particular worker. In addition, some jurisdictions only permit a hair follicle drug test for pre-employment, while other states may outright forbid its usage.
Authorities may impose drug tests for those on probation and in matters involving child custody, adoption, and domestic violence. In addition, medical practitioners occasionally ask for testing for patients at risk of alcohol or drug abuse. However, it is crucial to remember that drug testing requires a person's written consent.
What Are the Steps of a Hair Follicle Drug Test?
A hair follicle drug test may be conducted in a hospital or laboratory, at work, at home, or in other locations. A hair sample from the subject's scalp will be taken during the test and sent to a laboratory for overnight testing.
Prescription drugs and particular foods, such as poppy seeds, may include ingredients that could cause false positive findings. Therefore, two steps are taken with hair samples for proper test findings.
Enzyme-linked immunosorbent assay (ELISA), a quick screening approach, is used in the first phase.
A technician will repeat the hair sample testing using confirmatory chromatographic testing, such as gas chromatography-mass spectrometry (GC-MS), to help rule out false positives if the ELISA test yields a positive result for a specific substance.
What Is the Method of Using the Hair Follicle Drug Test?
Online vendors offer at-home hair follicle testing kits. An instruction manual and pre-paid envelope for mailing the hair sample to the laboratory are both included in these kits. The following are the steps to use a home test kit:
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Read the kit's instruction manual in its entirety.
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As directed by the manufacturer, collect a hair sample.
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Place the hair sample into a foil wrapper.
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Insert the accompanying envelope with the foil-wrapped hair inside.
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Send the package to the laboratory for examination.
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A person can see their test results by calling a toll-free number or logging in online and entering the unique identification number provided with the kit.
How to Interpret the Results?
The results of hair follicle tests can be positive, negative, or inconclusive:
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Negative: A negative result suggests that the laboratory could not confirm the positive ELISA screening results using GC-MS or did not detect any drug metabolites in the hair sample.
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Positive: A second test, such as GC-MS, will be performed on positive hair samples that yield a positive result during ELISA testing. A good outcome from confirmatory testing indicates that the laboratory found specific drug metabolites in the subject's hair sample.
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Inconclusive: The laboratory may declare inconclusive results if the hair sample is contaminated or if something needs to be fixed while testing. In these circumstances, a person might have to give the laboratory a fresh piece of hair.
Is Hair Follicle Drug Test Accurate?
Drug testing on the hair follicles can reveal whether a person has used a particular substance during the last three months. However, because of the wide variations in hair growth rates between individuals, these tests cannot determine the precise date of drug usage.
Hair samples are only sometimes correct despite going through a two-step testing process. The following variables may have an impact on the number of drug metabolites found in a hair sample:
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The composition of drug compounds.
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The number of drugs ingested.
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The amount of sweating.
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The amount of melanin (dark hair pigment) in the subject's hair — Certain medications adhere to melanin more readily when the hair is bleached or colored.
Using standard shampoos and styling products should not impact the test findings. Researchers compared self-reported drug usage with the results of hair follicle testing from 360 persons at risk for moderate drug use in a study looking at the efficacy of these tests. The study's findings show that drug testing on hair follicles successfully identified the following:
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52.3 % of those admitted to using cannabis recently.
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65.2 % of those admitted to recently using cocaine.
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24.2 % of those admitted to recently using Amphetamines.
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2.9 % of those admitted to recently using Opioids.
Researchers compared 3,643 participants' self-reported drug usage with the results of hair follicle drug tests in a cohort study. The test results showed more potential false negatives than the researcher anticipated but fewer potential false positives.
The study's findings led the researchers to conclude that hair follicle testing does not offer accurate information on drug usage in the general public.
What if a Person Does Not Have Hair on Their Head?
People who don't have hair on their heads can still undergo a hair follicle drug test because hair samples can be taken from the armpit or the cheek. In addition, the length of a person's hair must be at least 0.5 to 1.5 inches. So, for example, a person with shorter hair may need to provide more hair.
A suitable hair sample may not be available for people who shave their entire body.
Conclusion
Hair samples taken from the scalp are used in hair follicle tests, which can identify drug usage up to three months before testing. Despite going through a two-step testing process, hair samples are not always correct. The structure of drug compounds is one factor that may impact the concentration of drug metabolites found in a hair sample and how many drugs a person has ingested.
