Drug testing methods and cheating

Court-ordered drug tests are performed every day across Ireland for a variety of reasons, from local authorities making decisions about a child’s welfare, to family courts handling custody disputes.

However, not all legal clients are aware of which drug tests can best determine an individual’s pattern of substance abuse, or the ways in which people attempt to cheat a drugs test.

Before instructing a drug test, it helps to understand the testing methods available, and what different samples can tell us about a person’s drug use.

In this article, we look at the options available for court-approved drug testing, and the ways people try to cheat drug tests.

How do drug tests work?

Drug tests work by using laboratory analysis to detect the presence of drugs and their metabolites in a person’s sample.

When a person consumes drugs, they are broken down by the liver, and a proportion of the drug and its metabolites are released into the bloodstream.

This can then be detected using laboratory testing, which can identify the presence of the drug or drug metabolites in sweat, urine, saliva, hair and nails.

In the case of hair and nails, a proportion of the drug and its metabolites travel to the blood vessels in the scalp and nail bed.

Substances then become trapped in the hair shaft (medulla) and the keratin fibres of the nails, remaining in hair and nails as they grow, and making it possible to determine whether someone has consumed drugs, using hair and/or nail testing.

What are the different types of drug test?

There are several options available for court-approved drug testing: each method using a different sample type and offering a differing insight into an individual’s drug use.

The below table shows the types of drug test available, and the length of time drugs and their metabolites remain detectable after they have been consumed, depending on the sample type being tested.

Test Type Detection Window
Head hair Up to 12 months.
Overview analysis or month-by-month segmentation available
Body hair Overview of up to 12 months
Nails Six-month overview (fingernail clippings)
12-month overview (toenail clippings)
Urine Up to four days
Oral fluid (saliva) Up to 48 hours

Hair drug tests and nail drug tests both offer what is known as a ‘wide window’ of detection for drug use. This means that these tests can be used to paint a historic picture of an individual’s substance misuse.

Urine drug tests and oral fluid drug tests each offer a ‘narrow window’, meaning that drugs and their metabolites are only detectable for a short period of time following consumption.

Is it possible to cheat a drug test?

Advances in modern toxicology mean that it is extremely difficult to ‘trick’ a drug test into giving a negative result when a person has been misusing substances.

Although some attempts to cheat the test have the potential to impact results (e.g. drinking lots of water or excessively straightening hair) by diluting or reducing the amount of drug metabolites present in the sample, the test would still be able to detect the presence of these substances above cut-off levels.

Therefore, it is extremely likely that the person attempting to cheat the test would fail, due to the sensitivity of the equipment used to perform laboratory testing, and the expertise of toxicologists working in the laboratory.

Samples for legally-instructed drug tests are also collected under strict chain of custody conditions by a trained sample collector, reducing the likelihood of sample tampering, and making it incredibly difficult for sample donors to interfere with the testing process before/during sample collection.

How do people try to cheat drug tests?

For drug test results to be admissible in court, samples must be collected under strict chain of custody conditions, reducing the likelihood of tampering, and ensuring samples are collected from the right people.

Yet there are still some individuals who will attempt to ‘cheat’ a drug test; something which can be easily prevented by using a trained sample collector.

Common methods include:

  • Bringing another person’s ‘clean’ urine sample to a collection appointment
  • Attempting to dilute a urine sample by adding other substances
  • Wearing a wig
  • Attempting to pass off someone else’s pre-cut hair/nail sample as their own
  • Shaving their head prior to sample collection
  • Cutting nails prior to sample collection

While these methods are ineffective, it is important to note that excessive bleaching, dyeing, perming, or straightening of the hair has the potential to impact a drug test result.

For this reason, we will always ask for full disclosure of any recent hair treatments so that this can be taken into consideration when preparing the results.

Whatever the circumstances, a trained sample collector – such as those in AlphaBiolabs’ nationwide sample collection network and Dublin walk-in centre – will know how to spot the signs of tampering and will be able to collect an alternative sample on the day if required (e.g. body hair instead of head hair).

What happens if the sample can’t be collected?

There are some circumstances where an individual’s attempt to cheat a drug test might prevent the sample collector from obtaining the required sample.

For example, if a nail drug test were instructed, and it was found that the sample donor had cut their fingernails and toenails prior to collection, it may not be possible for the sample collector to retrieve nail clippings for testing.

Fortunately, experienced sample collectors, such as those at AlphaBiolabs, are trained to recognise the signs of someone attempting to avoid a drug test.

In this instance, provided the court did not request a specific sample, the sample collector would collect an alternative sample for testing (e.g. head hair or body hair).

However, if the court has ordered a specific sample for testing that cannot be collected on the day, an alternative appointment may need to be arranged for a later date to collect the correct sample.

Where can I order a drug test for court?

Understanding which drug testing methods will best suit your client, along with the ways that people try to cheat drug tests, will help you secure a satisfactory outcome for your case.

At AlphaBiolabs, we have over 15 years’ experience providing first-class drug testing services for the legal sector, from sample collection to laboratory analysis and reporting.

We also offer free sample collection for legally-instructed drug tests from our Dublin walk-in centre.

For expert advice on which drug test is best for your client, call our Legal team on 01 402 9466 or email and a member of the team will be in touch to discuss your needs.

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Ashley Hodgkinson AlphaBiolabs

Ashley Hodgkinson

Collections Manager at AlphaBiolabs

Ashley oversees the day-to-day management of AlphaBiolabs’ sample collections department and a team of specially trained clinicians who operate across the UK.

The role involves delivering the best possible service for clients, ensuring that sample collections are completed in a timely fashion and to the highest standard, often under strict chain of custody conditions.

Ashley has also worked with the AlphaBiolabs legal testing team to produce a series of webinars designed to educate legal clients on the intricacies of drug and alcohol testing and has delivered a number of bespoke training sessions to the Judicial College.

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