Harcourt ChambersCoram Chambers1 CORimage of 4 Paper Buildings logoAlpha BiolabsFamily Law Week Email Subscriptionsite by Zehuti

Hair-strand testing comes under judicial scrutiny in child care case

Mr Justice Baker gives judgment in case concerning conflicting hair-strand expert evidence

Mr Justice Baker has given judgment in proceedings where the reliability of hair-strand testing methods has come under detailed scrutiny.

In the case of Bristol City Council v A and A, and SB and CB, and Concateno and Trimega (interveners) [2012] EWHC 2548 (Fam), a mother involved in care proceedings had been hair-strand tested in order to establish whether she was continuing to take drugs. She underwent a test carried out in June 2011 by Trimega Laboratories Ltd. The results purported to show that the mother had been using increasing amounts of cocaine and opiates right up to the date of the sample being taken. The mother, however, vehemently denied that this was the case, and she was therefore given permission to obtain a second analysis on a sample taken at the same time. The results of the second test, carried out by Concateno Cardiff Ltd (also known as TrichoTech), appeared to confirm the mother's version that that she had not used drugs as described or at all for approximately the previous four months.

In view of the 'stark conflict of expert evidence', Concateno and Trimega were given permission to intervene in the proceedings which were listed before the President, Sir Nicholas Wall.

The specific issues were:

(1) Which of the drugs tests on the mother's hair sample provides accurate and reliable evidence:

(a) Trimega only;
(b) Concateno only;
(c) both Trimega and Concateno; or
(d) neither?

(2) In the light of the court's answers to question 1, what findings should the court make in relation to the mother's drug use?

(3) What general guidance, if any, should be given to family courts about the use and interpretation of, and reliance upon, hair testing in the light of the apparent inconsistencies in the testing results provided by the two companies?  Does hair testing remain a reliable method for determining drug use in family courts?

It was conceded by Trimega shortly prior to the hearing before the President that its analysis was erroneous and unreliable although the precise error remains unclear. It was believed by Trimega that a human error in the collection process was responsible.

This concession effectively resolved the first two issues and the court accepted that the scientific evidence demonstrated that the mother had used class A drugs until early 2011 but had been abstinent for five months prior to the hearing. As a result, the court directed a community-based assessment under s.38 (6). The President's order made no reference to the third issue.

The remaining third issue was considered by Baker J in proceedings attended by the two intervening parties.

For Concateno, Robin Tolson QC of St John's Chambers (instructed by Wragge & Co) argued that:

(1) Trimega's inadequacies risked belittling and damaging the reputation of this important testing and the companies carrying it out ….'Trimega risked throwing out the industry's healthy baby with the bathwater that is Trimega's own'.

(2) The court should accept four general propositions about the use of hair-strand testing for drugs which were agreed between the interveners at the hearing before the President and which he submitted were uncontroversial. Those propositions were:

a. The science is now well-established and not controversial.
b. A positive identification of a drug at a quantity above the cut-off level is reliable as evidence that the donor has been exposed to the drug in question.
c. Sequential testing of sections is a good guide to the pattern of use revealed.
d. The quantity of drug in any given section is not proof of the quantity actually used in that period but is a good guide to the relative level of use (low, medium, high) over time.

(3) The court should consider giving more specific guidance, in particular that international standard ISO/IEC 17025:2005 provides "the gold standard" for laboratories carrying out tests of this kind and that formal laboratory accreditation to this standard provides assurance of quality that the standards are being met.

Piers Pressdee QC of 29 Bedford Row (instructed by Hanne & Co) for Trimega, contended that:

(1) Any further consideration of either the 'third issue' left unresolved by the President or the details of Trimega's error(s) was neither necessary nor appropriate, nor consistent with the overriding objective set out in the Public Law Outline.

(2) Any guidance would affect not just the interveners but every other drugs company offering or looking to offer a hair strand drugs testing service to family courts.

(3)  The primary motivation of Concateno was to obtain a judgment critical of Trimega, and guidance from the court, that could be used for commercial advantage.

Baker J determined:

"The integrity of the science, and the validity of hair strand testing for drugs, is unaffected by this case. There is, therefore, no proven need for a general inquiry into the matter, or for detailed guidance as to how such tests should be carried out or used in court proceedings.

.... [T]his court is not the appropriate forum for any such inquiry."

The court endorsed the four general propositions concerning the use of hair-strand testing set out above but declined to promulgate any more detailed guidance.

Baker J added:

"I conclude by emphasising again that in appropriate circumstances the family justice system requires, and will continue to require, expert evidence to ensure that it makes the right decisions about the future of children. I repeat what I said in Re JS [2012] EWHC 1370 (Fam) at para 47:

'Whilst the courts always have to be vigilant to guard against the proliferation of experts in family proceedings, the court must, in my judgment, always have available to it the necessary expertise to make the right findings in these important and difficult cases.'

As Ryder J has recently observed in "Judicial Proposals for the Modernisation of Family Justice" (July 2012) (at para 41):

'In every case, the judge should be able to say: is your expert necessary i.e. to what issue does the evidence go, is it relevant to the ultimate decision, is it proportionate, is the expertise out with the skill and expertise of the court and those already involved as witnesses by reference to the published and accepted research upon which they can rely and of which the court has knowledge.'

Plainly hair strand testing for drugs satisfies all of these criteria. But as this case illustrates, a high degree of responsibility is entrusted to expert witnesses in family cases. Erroneous expert evidence may lead to the gravest miscarriage of justice imaginable – the wrongful removal of children from their families."

The judgment can be read in full here. For an article on the decision in Re JS, written by Henry Lamb of 14 Gray's Inn  Square at the time of the judgment, please click here.