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The Honourable Mr Justice Peter Jackson Endorses Hair Strand Testing in Family Law Cases

In an unprecedented move, the Honourable Mr Justice Peter Jackson recently invited UK hair drug testing providers to intervene in a child custody case* with the aim of the court assessing the science of hair drug testing and its importance in family law.

Lextox and two others accepted the invitation and gave extensive evidence in the intervention hearing.

The full judgment can be found here.

The key outcomes from the intervention hearing in relation to hair strand testing and how it is delivered are:

Hair Strand Testing in Family Law

The judgment confirmed that hair strand tests can provide important information, and that the Expert should be able to describe the process, record the results and explain the significance in a way that can be clearly understood.

The ability to work in this field requires the drug testing organisations to be accredited and validated to the required standard.

In respect of the evidence submitted by Lextox to support hair strand testing in family law, Mr Justice Peter Jackson accepted the very full evidence submitted and is “satisfied that they have done everything they can to help the court”.

The Need for Experienced Experts

In this case the donor claimed positive hair test results for cocaine were due to environmental exposure rather than ingestion and submitted a trichologist’s report questioning the credibility of hair testing science.

However, Mr Justice Peter Jackson rejected the arguments of the trichologist and noted that his expertise did not extend into toxicology. The trichologist’s criticisms of hair testing science were not supported.

Angharad John, Senior Reporting Scientist at Lextox, was recognised as having “enormous experience of giving opinions on hair strand tests” and her submissions were “evidence-based and carefully considered”.

The conclusions of the hair testing Experts tipped the scales against the opposing arguments in the case.

Mr Justice Peter Jackson reiterated that “experience is key”.

Reporting Suggestions

Mr Justice Peter Jackson also provided a number of suggestions for hair testing organisations working in family law. Many of these are already employed by Lextox in its existing practices, such as giving an opinion on whether the levels detected are high, medium or low.

The SoHT (Society of Hair Testing) guidelines were acknowledged as the current industry standard for family law, and as such Lextox has always followed them.

A key suggested change is that very low level values, which are even below the SoHT guidelines for reporting cut off values, are provided in the reports produced for court, to ensure the court has all the necessary information to make the correct and most informed decisions.

The company plans to adopt and implement the Judge’s suggestion on reporting very low level values, below the SoHT’s cut off guidelines, subject to approval by UKAS (United Kingdom Accreditation Service), the UK’s governing body for ISO 17025 accreditation.


This case reinforces the importance of hair testing in family law and childcare casework.

In providing legally defensible opinion-based evidence, working on the balance of probabilities, hair testing Experts need to understand many factors including the laboratory sample wash and analysis procedures, effects of hair growth rate, and environmental exposure for example, as well as the toxicology itself.

Mr Justice Peter Jackson agreed that experience is key. He found that Lextox has the necessary accreditation, and regularly submits its procedures for external validation. The judge concluded that Lextox provided very full information, and had done everything it could to help the court.

The case emphasises the need for experienced Experts in toxicological hair testing to accurately interpret the analysis results.

Lextox Evidence for Family Courts

The reliability of our results and Expert opinions in family law cases are our top priority.

All Lextox Reporting Scientists are Bond Solon court trained, are based at Lextox’s UK hair testing laboratory and have first-hand access to the laboratory analysis procedures.

Our team of 10 Expert Witnesses specialising in hair drug and alcohol testing for family law is the largest laboratory based team in the UK, and includes some of the most experienced individuals in the industry.

Lextox is accredited to ISO 17025 testing standards by UKAS the United Kingdom Accreditation Service.

Our laboratory analysis procedures and reports are in accordance with the SoHT consensus.

If you have any questions on this case or on hair drug and alcohol testing please email [email protected].

*Case: Re H: Hair Strand Testing, before The Honourable Mr Justice Peter Jackson. Judgment Date: 29 September 2017

Published 10/10/17 – All information correct at time of publication