Family lawyers at risk of misinterpreting alcohol test results

AlphaBiolabs, DNA, Drug and Alcohol testing laboratory, is advising family law practitioners to be aware of the limitations of alcohol testing when providing legal evidence. Alphabiolabs, offers a nationwide service, and claims it regularly receives enquiries from family law solicitors and judges who are not fully aware of the science of the testing and subsequently, how results should be interpreted. “There are many factors that must be taken into account when interpreting alcohol testing results performed to determine chronic and excessive alcohol use. Indeed, it is also important to remember that any scientific evidence must not be considered alone, but in conjunction with all other evidence available in a case” explains AlphaBiolabs director, David Thomas. The most common questions received by the laboratory from those practicing family law include: What is chronic and excessive alcohol consumption? At present, according to the World Health Organization (WHO), chronic excessive alcohol drinking corresponds to an average consumption of at least 60 grams of pure ethanol per day. This equates to approximately 7.5 units of alcohol, or approximately 3 pints of beer or 2 to 3 large glasses of wine (depending on the alcoholic strength of the beer and wine) over several months. Indeed, it is very important to note that this consumption must be over a considerable period of time. Is it possible that EtG and FAEE hair test results performed on the same individual can sometimes give conflicting results? Because EtG and FAEE are formed and incorporated into the hair by different mechanisms, there are occasions where both results are conflicting. In such cases the tests performed cannot provide a clear “yes” or “no” answer to the question of chronic and excessive alcohol consumption. This disparity in findings can also be caused by factors such as:
  • The possible removal of EtG through very frequent shampooing as well as cosmetic hair treatments (e.g. dye/bleach).
  • The direct application of cosmetic products containing alcohol (such as hair spray, mousse, gel and wax) causing false positive FAEE results.
These issues were considered in the ruling of LB Richmond v B & W & B & CB (2010) EWHC 2903 (Fam), which recommends that:
  • When used, hair tests should only ever be used as part of the evidential picture. Indeed, the hair analysis findings should not be used in isolation but in conjunction with all evidence for the case including witness reports, other tests performed and any clinical assessments carried out.
  • Because of the respective strengths and weaknesses of EtG and FAEE tests, if hair tests are being undertaken, both tests should be performed and their findings should support each other in order to determine excessive and chronic consumption of alcohol.
  • Does an elevated γ-Glutamyl Transpeptidase (GGT) result in a Liver Function Test (LFT) mean that an individual has consumed alcohol chronically and excessively?
LFTs are commonly used as a general indicator of liver disorder, reflecting possible hepatocyte injury or cholestasis (blockages or damage in the biliary system), but the results themselves can give clues to the causes of liver damage. Historically, an increase of GGT, one of the enzymes monitored in a LFT, has been used to indicate chronic and excessive alcohol consumption. However, it is accepted that this conventional marker has both imperfect sensitivity and specificity. Indeed, an elevation of GGT has been reported in pancreatic disease, myocardial infarction, chronic obstructive pulmonary disease, renal failure, obesity, smoking, diabetes mellitus, pancreatitis, hyperthyroidism and severe trauma. With regards to sensitivity, it has been reported that for a healthy individual, at least 60 grams of alcohol per day, for a minimum of five weeks is required before an elevation of GGT may be observed, but that only 30–50 percent of excessive drinkers in the general population will show an increased GGT result. Overall therefore, it is now generally accepted that GGT alone has failed to provide adequate sensitivity and/or specificity to be clinically or legally useful, but may be of value if used and interpreted in conjunction with other bio-markers, such as CDT. “If relying upon these tests, both family lawyers and judges need to be fully aware of how they should be used, particularly as individuals are becoming more knowledgeable about how results can be affected”, says David Thomas “Legal knowledge in these instances is not enough, and should be supported by an understanding of the actual analytical tests being performed and their strengths and weaknesses”.