Hair drug test vs. oral fluid/saliva drug test

Gail Evans, Alphabiolabs

By Gail Evans, Technical Trainer at AlphaBiolabs
Last reviewed: 05/04/2023

Both hair drug testing and oral fluid or saliva drug testing can be used to determine an individual’s drug consumption. However, there are several differences between the two tests.

In this article, we explore hair versus saliva drug testing, the benefits of each and what the results can determine about an individual’s pattern of drug use.

Table of contents
  • How can drugs be detected using drug testing?
  • What is a hair drug test?
  • How does hair drug testing work and how can drugs be detected in hair?
  • How accurate and reliable is a hair drug test?
  • How long can drugs be detected in hair?
  • What drugs can be detected using hair drug testing?
  • How are hair samples collected for testing?
  • What are the benefits of hair drug testing?
  • What is an oral fluid/saliva drug test?
  • How does a saliva drug test work?
  • How accurate and reliable is a saliva drug test?
  • What is the detection window for drugs in oral fluid testing?
  • What drugs can be detected through saliva drug testing?
  • How are saliva samples collected for testing?
  • What are the benefits of saliva drug testing?
  • Which drug testing method is best? Hair drug testing or saliva drug testing?
  • Where can I get a hair drug test or a saliva drug test?

How can drugs be detected using drug testing?

When an individual consumes drugs, they are broken down by the liver. A proportion of the drug and its metabolites are absorbed into the bloodstream, whilst some of the drug is excreted from the body in a variety of ways, including though urine and saliva.

This makes it possible to analyse a variety of samples and determine whether drugs and their metabolites are present in hair, nails, oral fluid (saliva) and urine. Although saliva and urine drug testing can only show us whether an individual has used drugs in the past few days, the rate at which hair and nails grow means that hair drug testing and nail drug testing can offer a wider window of detection.

What is a hair drug test?

A hair drug test, also known as a hair follicle test or a hair strand test, is when a sample of head hair or body hair is analysed for the presence of drugs and their metabolites.

When someone consumes drugs, they are broken down by the liver and passed into the bloodstream, through which the parent drug and a proportion of the drug’s metabolites enter the hair follicle and become trapped in the medulla, the innermost layer of the hair shaft. This makes it possible to detect the drugs during analysis of the hair at the toxicology laboratory.

How does hair drug testing work and how can drugs be detected in hair?

As mentioned, when someone consumes drugs, they are broken down by the liver and absorbed into the bloodstream. The parent drug and a proportion of the drug’s metabolites then enter the hair follicle and become trapped in the medulla, the innermost layer of the hair shaft.

It takes up to 10 days for the hair to grow above the scalp’s surface. After another two weeks, this hair strand is ready to be included in a cut sample of hair.

There are two different types of head hair drug tests: overview analysis and segmented analysis.

Segmented analysis is the most detailed type of head hair drug test and provides a month-by-month profile of an individual’s drug use. Using this method, hair samples are segmented into 1cm sections. Segmented analysis can be used to identify patterns of drug use for up to 12 months (using 12 x 1cm sections of hair).

Overview analysis provides a more general picture of someone’s drug use. The maximum length of hair that can be tested is 3cm, which provides an overview of 3 months. Therefore, 4 x 3-month overviews can provide up to a 12-month profile. However, unlike segmented analysis, an overview analysis cannot determine exactly when the drugs were consumed within the period being analysed.  An overview analysis will only determine whether drug markers are present in the sample for that period.

If head hair is not available for testing, body hair can be analysed. The sample must be taken from the chest, leg, back, arm, face or underarm. Body hair cannot be segmented to provide a month-by-month profile because the rate of growth is not consistent. Body hair samples can therefore only be used to provide up to a 12-month overview of drug use.

How accurate and reliable is a hair drug test?

At AlphaBiolabs, our hair drug testing is 100% accurate and reliable based on the samples we receive at our laboratory.

We are accredited by UKAS to the quality technical standard of ISO 17025 (No. 2773) and certified to ISO 9001.

We follow cut-off guidelines for hair drug testing as set by the Society of Hair Testing, and our toxicologists also work within the framework of Family Law, following Part 25 of the Family Procedure Rules (2010).

How long can drugs be detected in hair?

Depending on the length of hair available for testing, and when the drugs were consumed, hair drug testing can provide a window of detection of up to 12 months.

Head hair can be segmented into 1cm sections to provide a month-by-month profile for up to one year.

Body hair cannot be segmented as it has a much more variable growth rate than head hair and can therefore only be used to provide an overview of drug use for up to 12 months.

What drugs can be detected using hair drug testing?

At AlphaBiolabs, our hair drug tests can detect a wide range of substances, including:

We also offer a Drug Screen Plus service, which can tell you whether any additional substances were present in the sample that you didn’t specifically ask us to test for. We can also arrange hair drug testing for substances including GHB, LSD, Spice, steroids, and Tramadol, for an additional fee.

How are hair samples collected for testing?

Samples for legally-instructed hair drug tests are collected by trained AlphaBiolabs sample collectors under strict chain of custody conditions, to ensure that samples are collected from the right people and to prevent tampering.

When the individual arrives at their appointment, a photograph will be taken of them, and they will be required to show suitable photographic identification. Our professional sample collectors will then ask them to disclose any medication and recent hair treatments, as these can potentially impact the drug test result.

The sample needs to contain around 200 strands of hair. As collection of the hair sample will leave a small bald patch, the collector will assess the most discreet and suitable sample site. This is usually at the back of the head.

Ideally, the hair sample will be taken from an area around the highest point of the scalp, as this has the least variation in growth rate. However, the exact sample site may depend on the length of hair required for analysis.

A hair sample cannot be shaved or plucked and must be cut by the professional sample collector at the appointment.

If head hair is not available, body hair can be collected from the face, leg, arm, back, chest or underarm.

What are the benefits of hair drug testing?

One of the biggest benefits of hair follicle drug testing compared to other types of drug testing is that it is able to show a longer history of drug use. Head hair drug tests can also be used to create month-by-month profiles, which can be used to determine a detailed pattern of drug usage.

Hair drug testing can also be used to detect a wide range of drugs and the results are 100% reliable.  When samples are collected by a professional AlphaBiolabs sample collector, it is also impossible to ‘cheat’ a hair drug test.

What is an oral fluid/saliva drug test?

Oral fluid or saliva drug testing is the method of analysing someone’s saliva to determine whether they have been taking drugs.

It provides either an immediate negative result, which means that no further action is required, or a non-negative result, which means that further testing via a toxicology laboratory is required.

This type of drug testing is known as ‘narrow window’ testing, as the period of detection is up to 48 hours.

How does a saliva drug test work?

When a person consumes drugs, they are broken down by the liver. A proportion of the drug and its metabolites are absorbed into the bloodstream, whilst some of the drug is excreted from the body in a variety of ways, including though urine and saliva.

This makes it possible to analyse a variety of samples and determine whether drugs and their metabolites are present in hair, nails, urine or oral fluid (saliva).

An oral fluid or saliva drug test is performed by using a self-contained oral fluid device to take a sample of a person’s saliva.

How accurate and reliable is a saliva drug test?

Oral fluid (saliva) drug tests are extremely accurate and reliable.

Our professional sample collectors follow strict procedures throughout the process to ensure that chain of custody is maintained and to prevent sample tampering.

What is the detection window for drugs in oral fluid tests?

Oral fluid drug tests are known as ‘narrow window’ tests as they provide a window of detection of up to 48 hours. This means that this type of test can only confirm whether someone has been using drugs in the two days prior to the sample being collected.

Those who require a wider window of detection or a historic overview of an individual’s drug use should consider nail drug testing or hair drug testing. These types of tests can provide a wider window of detection of up to 12 months.

What drugs can be detected through saliva drug testing?

At AlphaBiolabs, the main drugs that our oral fluid drug test screens for are:

  • Amphetamines
  • Cannabis
  • Cocaine
  • Methamphetamines
  • Opiates
  • Benzodiazepines

How are saliva samples collected for testing?

An oral fluid or saliva drug test is performed using a small self-contained oral fluid testing device.

The device usually comes with an absorbent sample collector that the individual must rub around the inside of their mouth to collect the appropriate sample of saliva. Once the individual has completed this stage, the absorbent material is inserted into the test cassette for analysis.

For a negative result, a line will appear next to the substance classes on the device.

A non-negative result is when no line appears next to one or more of the substance classes on the device.

In the event of a non-negative result, two additional saliva samples are required and will be returned to the AlphaBiolabs toxicology laboratory for confirmatory analysis.

What are the benefits of saliva drug testing?

The main benefit of saliva drug testing is that it provides an immediate screening result.  It is quick, efficient and highly reliable.

Oral fluid drug testing has become increasingly popular over urine drug testing as a form of ‘narrow window’ detection, as it offers a more discreet, hygienic, and non-invasive way to carry out ‘narrow window’ drug testing.

Which drug testing method is best? Hair drug testing or saliva drug testing?

Both hair drug testing and saliva drug testing are effective ways to determine if someone has been using drugs.

The biggest difference is that saliva/oral fluid tests provide a detection window of up to 48 hours and can therefore tell us if someone has been using drugs in the days immediately before the sample was collected. Hair drug tests, on the other hand, can provide a historic view of someone’s drug use for up to 12 months.

Oral fluid tests provide immediate screening results, whereas hair drug testing requires back-to-lab analysis.

This means that oral fluid drug tests are best used when it is suspected that someone might be under the influence of drugs in the ‘here and now’, whereas hair drug tests are more beneficial if you want a historic profile of someone’s long-term drug use or abstinence.

Where can I get a hair drug test or a saliva drug test?

AlphaBiolabs has extensive experience providing drug testing services for local authorities, family law professionals and social workers. We have invested in the very latest technology for our state-of-the-art toxicology laboratory, employing the very best scientists, so you can be confident of receiving a 100% accurate result.

We have a UK-wide network of professional sample collectors, and all sample collections are performed under strict chain of custody conditions.

We also offer free sample collection for legally-instructed drug tests from any of our nationwide walk-in centres.

For expert advice on which testing method is best for your client, or to request a quote, call AlphaBiolabs’ Legal team on 0333 600 1300 or email testing@alphabiolabs.com.

Alternatively, complete our online quote form, and a member of the team will be in touch to discuss your needs.

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Gail Evans, AlphaBiolabs

Gail Evans

Technical Trainer at AlphaBiolabs

A professionally-trained forensic scientist, Gail joined AlphaBiolabs in 2012 and holds the role of Technical Trainer.

Her day-to-day responsibilities include delivering in-depth training sessions both internally and externally, covering DNA, drug, and alcohol testing.

Throughout her career at AlphaBiolabs, Gail has held a variety of roles, including within the Legal and Workplace sectors of the business.

Before joining the company, Gail was a practicing forensic scientist with 25 years’ experience working for the Forensic Science Service, attending scenes of crime, and analysing physical and biological material with potential evidential value.

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