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Hair strand testing in the family courts — is it reliable?

Hair strand testing is often used in children proceedings where there is a suggestion that a parent has been using illegal substances but how reliable…

Hair strand testing is not a new concept and is routinely used in both private and public children proceedings where there is a suggestion by a parent that the other parent is or has been using illegal substances. It is not uncommon for the court to stay proceedings to direct that hair strand testing is carried out before the court can determine the amount of time a child can spend with their parent.

Whether a parent should or should not have contact with a child in this context depends on the drugs being taken, the usage and the impact upon the parent being able to provide safe and appropriate care for a child. A common sense approach is often taken by the courts whose paramount consideration is always the welfare of any child and often results in parents receiving supervised contact on an interim basis until they can overcome their addiction. The courts will look at the context and background of the parties and will be less than impressed where a mother and father have a background of recreational drug use and on separation the primary carer decides to use this as a reason to try and defeat contact between the child and non-resident parent.

Hair strand testing is only indicative of the degree of consumption but these test results should only be used as a guideline and further investigation is often required to avoid miscarriages of justice. There have been a number of cases where parents have reported historical drug use which has generated positive test results and the test companies often categorise the results as moderate, medium or high users of drugs. Does this mean a parent has “fallen off the wagon” or could the error lie in the categorisation of the results or in the labs themselves?

In the case of Bristol City Council v A and A and SB and CB, and Concateno and Trimega (interveners) [2012] EWHC 2548 (Fam) the reliability of hair strand testing came under scrutiny. A mother involved in care proceedings was hair strand tested to establish whether she was continuing to take drugs. The results showed the mother had been using increasing amounts of cocaine and opiates up to the date of the sample being taken. The mother denied this was the case and a second sample was taken and tested by another laboratory which supported the mother’s position that she had not used drugs for the past four months. The two drug-testing companies were invited to join the proceedings before Sir Nicholas Wall. Trimega conceded prior to the hearing that its analysis was erroneous and unreliable and believe this was due to human error in the collection process.

The court then looked at what general guidance, if any, should be given to family courts about the use and interpretation of, and reliance upon, hair testing, whether it remains a reliable method for determining drug use in the family courts. The court endorsed the 4 propositions put forward by the drug testing companies but felt that there was no need for a general inquiry into the matter or for detailed guidance as to how such tests should be used and that the court is not the appropriate forum for any such inquiry. The 4 agreed propositions were as follows:

  1. The science of drug-testing is now well established and uncontroversial
  2. A positive identification of a drug at a quantity above the cut off level is liable as evidence that the donor has been exposed to the drug;
  3. Sequential testing of sections is a good guide to the pattern of drug use; and
  4. The quantity of drug in any given section is not proof of the quantity used in that period but is a good guide to the relative level of use over time.

Jackson J looked the issue of hair strand testing more recently in the case of Re H (A Child Hair Strand Testing) [2017] EWFC 64 where 3 laboratories were involved in testing a mother for cocaine use. Jackson J heard evidence from 5 experts including a jointly instructed Forensic Toxicologist and noted the variations in the approaches taken by different drug testing companies, for example one company’s high usage figure would be another’s medium usage figure. He stated that hair strand test results should not be used to reach evidential conclusions by themselves, in isolation of other evidence. That the results should never be regarded as determinative and that it was a matter for the judge to evaluate alongside the broader evidential picture which includes social work and medical evidence and the reliability of the account given by the donor.

Jackson J reported that there are 9 accredited hair strand testing organisations working within the family law arena and he made 7 suggestions under the following headings for the organisations to take on board when reporting as follows:

  1. Use of the high/medium/low descriptor;
  2. Reporting of data below the cut-off range;
  3. Terminology used;
  4. Expressions of probability;
  5. Environmental contamination;
  6. Essential information;
  7. Variable findings;

Most cases do not hinge on the result of one drug test alone but depend on a parent being able to establish and maintain abstinence from substance misuse and being able to demonstrate that in the longer-term. A cautious approach needs to be taken when interpreting drug testing results and they are one consideration not be considered in isolation. It is vitally important the family court continues to consider the wider context taking into account the particular circumstances of the family in question.

It remains to be seen whether Jackson J’s comments will be taken on board by the drug testing companies going forwards. However there are still a number of different factors which can influence test results such as over the counter medications, method of ingestion, grade of substance, recent medical procedures under anaesthetic, hair dye, the weight of the sample, and cross-contamination of samples. It is important that these factors are explored with clients at an early stage and discussed with the drug testing company prior to the sample being taken in an effort to improve the accuracy of the report.

It also emphasises the importance of seeking legal advice as soon as possible within proceedings to explore these issues at an early stage before the test results are received. 

Linzi Perriman is a solicitor in the family law team

For further information on hair strand testing in the family courts, contact our family lawyers.

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