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Hair Strand Testing for Alcohol: Hair today, gone tomorrow?

Henry Lamb of 14 Gray's Inn Square summarises the findings of Moylan J in LB of Richmond v B (the 'hair test' case)

 Henry Lamb, Barrister, 14 Gray's Inn Square

Henry Lamb, Barrister, of 14 Gray's Inn Square

Mr. Justice Moylan has recently provided guidance in London Borough of Richmond upon Thams v B [2010] EWCA 2903 (Fam) as to the use of hair strand testing for alcohol in Children Act proceedings.  The judgment sets out in detail the forms of hair strand testing currently available and is also of note as it provides a clear reminder to experts who produce reports within Children Act proceedings of their duties under the Practice Direction 'Experts in Family Proceedings Relating to Children' (2009) 2 FLR 1383.  This article is intended to provide a summary of the salient points from the judgment and is no substitute for reading the judgment in full. 

Which test? 
Hair strand testing for alcohol currently takes one of two forms, one of which tests for the presence of "EtG" (ethyl glucuronide) and the other for "FAEE" (fatty acid ethyl esters).  Currently Trimega Laboratories provide tests for both and Trichotech test only for the presence of EtG.  Mr. Justice Moylan sets out in detail the two forms of testing, which shall not be repeated here, but a helpful way to understand the differences between the two forms of test is the water-loving (hydrophilic) nature of EtG markers. They are understood to be incorporated into hair through sweat and are therefore more susceptible to being washed out of the hair by shampooing.  FAEE are fat loving (lipophilic) and are consequently understood to be more resilient to washing, though it is understood that hair treatment products, such as peroxide hair bleach, may still reduce the levels found in the hair.  The judgment notes the potential benefit of using both forms of testing due to the respective strengths and weaknesses of each.

To show what level of alcohol use?
The judgment warns against the use of hair strand tests to test for lower levels of alcohol use.  Mr Justice Moylan held that is not possible for such tests to distinguish, at this time, between abstinence and social drinking, due to the lack of empirical data and ROC analysis as to where the appropriate "cut off" level should be, and Mr Justice Moylan therefore stated that 'in the absence of any peer reviewed and agreed cut off, any court would, in my view, need specific justification before accepting such evidence.'

This does not mean that it will never be possible for hair strand tests to demonstrate this in the future.  Further empirical research and data collection may lead the scientific community to reach consensus as to the appropriate "cut-off" point to demonstrate social drinking as opposed to abstinence.  The Society of Hair Testing will no doubt consider this in time and the hair testing companies will have to justify how they have come to any "cut off" that they can agree.  

How reliable is it?
Hair strand testing is generally still reliable to test for frequent and excessive consumption of alcohol.  This has to be read with the caveats that: 

  1. It is still possible for a parent to seek to reduce the level of detection by either shampooing or bleaching their hair. 
  2. It is still possible that the level of detection may be increased by, for example, the use of products on the hair which contain alcohol, or as a result of other factors including through alimentary alcohol being present in food (e.g. some breads). 
  3. The "cut-offs" for frequent and excessive consumption have been set through empirical research and ROC analysis, and are set at a point where the results were understood to produce 10% false positive and 10% false negative results.       
  4. The analysis of the hair strand test results should be for  a minimum period of  three months.   
  5. When used, the tests should only form part of the evidential picture.  However, where the results are 'very high' such results might form a 'significant part of the evidential picture'.

When should hair strand testing be used?
Much depends on what it is that is sought to be established.  If the issue is whether or not a parent has consumed alcohol at a frequent and excessive rate over a period of time (at least 3 months) then hair strand testing will still be useful evidence, as will blood (Carbohydrate Deficient Transferrin and / or liver function) tests.

If the issue is whether or not an individual is still consuming alcohol, albeit at levels that are not frequent and excessive, then random urine, swab or breathalyser tests may be of greater assistance.  Clinical observation is acknowledged to be an important part of the evidential picture in any event.  Mr Justice Moylan described the decision of the Local Authority in the case to test by way of urine samples in the future as being "sensible".  Although noting that such tests have their own inherent limitations, due to the length of time that ethanol remains in the blood or urine, he states that they 'form a more secure factual foundation' to demonstrate that alcohol has been consumed. 

The Experts Practice Direction
Mr Justice Moylan was critical of the failure by the experts in the case to follow the Practice Direction 'Experts in Family Proceedings Relating to Children' (2009) 2 FLR 1383.  The Practice Direction states that an expert's report should highlight whether the expert's opinion is qualified and whether there is a consensus within the scientific community. Where there is a range of expert opinion, the report should summarise the range, using a 'balance sheet' approach to the factors for and against an opinion if appropriate.  It is also incumbent upon an expert when expressing an opinion to highlight limited experience, lack of research, peer review or support, where relevant.

Mr. Justice Moylan stated:

'It is particularly important when new scientific tests are being used for forensic purposes that they have a sound basis which makes it appropriate for the results to be used in court proceedings and which is sufficiently explained so that the court and the parties have a full understanding of the evidential basis both of the tests themselves and of any opinions based on the interpretation of the results of such tests.'

The judgment agrees with the points indentified in Re F (Children) (DNA Evidence) [2007] EWHC 3235, [2008] 1 FLR 328 and warns experts in Children Act proceedings of the need to follow the Practice Direction, due to the serious consequences that their evidence may have on children and their families' lives.  Mr Justice Moylan stated in the final paragraph of his judgment 'this is not to blame the Local Authority for such reliance but rather is a proper reminder of the need for expert evidence to be given in a manner which accords with the principles underlying the Practice Direction' and he earlier observed that 'it is self evident why expert evidence needs to be given in accordance with the Practice Direction.  The court and the parties need to have available all the information necessary to understand what weight can be placed on the evidence.'

Hair strand testing for alcohol will continue to have important evidential value in Children Act proceedings to indicate frequent and excessive consumption.  Mr. Justice Moylan's judgment has provided useful guidance to practitioners in understanding the tests and the shortcomings that they have.  It will of course be important to consider in any individual case which the most appropriate forms of testing are and to consider, when hair strand testing is used, the factors that may be affecting the result.  It will also be important for the companies involved to be clear about what the results mean and to explain whether there is consensus amongst their peers in relation to the analysis of the results that are provided.  

Other tests may also become available and it will be necessary for the experts involved, if instructed, to follow the Practice Direction and to consider carefully the potential implications of the results that they provide.