Reforming The Hair Strand Testing Industry - Why Expert Interpretation Matters (21 May 2025)

• Published date: 26 May 2025
• Subject Matter: Food, Drugs, Healthcare, Life Sciences, Food and Drugs Law
• Law Firm: Duncan Lewis & Co Solicitors
• Author: Courtney Springall

For years, the family court system has relied heavily on simplified drug and alcohol test results. However, recent High Court and Court of Appeal rulings confirm that hair strand tests should be considered expert opinion evidence'not just laboratory results.

In D, Re (Children: Interim Care Order: Hair Strand Testing) [2024] EWCA Civ 498, Mr Justice Cobb concluded that Her Honour Judge Jacklin KC was wrong to attach "such presumptive weight" to the hair strand test results and that she did not consider sufficiently "the context of the broader picture" of evidence.

One of the grounds of the mother's appeal in this case was that the judge had formed erroneous conclusions about the hair strand testing results, wrongly treating the general opinion on the first laboratory as to its findings. Mr Justice Cobb agreed, and allowed the appeal. He said that the judge had been wrong to attach such weight to the...