Image of hair being tested

Segmented hair testing in family law cases

With so much riding on the results of drug and alcohol testing in family law cases, it is vital that consumption is tested in the most suitable way to ensure the accuracy of results and to show the full picture of someone’s drug or alcohol use.

Hair strand testing is widely recognised as a reliable testing method in family law cases when someone needs to prove reduction in or abstinence from drug and/or alcohol use. Compared to saliva and urine testing, which can only give a snapshot of a moment in time, a hair test can prove or disprove a history of use.

Here, Tyson Thomas, Reporting Scientist at Cansford Laboratories, explains why segmented hair testing should be the go-to method to build a more accurate picture of alcohol use in family law cases.

Why choose hair testing?

The hair testing process is considered reliable as it is closely controlled and monitored – from collection to transportation and analysis – producing robust results that can stand up in court as evidence of a client’s drug or alcohol use.

There are two types of hair testing methods used in the UK – overview and segmented. It is the latter which has caused much debate in the industry as to its suitability in alcohol testing, yet we believe that it is the best option to give a more detailed analysis of use over time.

Types of hair testing

It is important to understand the distinction between overview and segmentation hair testing to ensure the correct test method is selected.

Overview hair testing can provide a general indication of drug or alcohol use throughout a defined testing period, depending on the length of hair selected. An overview analysis will cover a whole section and identify drug use within that period. For instance, a 3cm overview can provide an integrated average result of use over the entire three-month period but will not specify trends of use within that time.

Segmentation provides a month by month break down, providing a more detailed history of a person’s drug or alcohol use. It is recommended in cases where drugs or alcohol have been used within or close to a particular time frame of the analysis, and evidence is needed that drug or alcohol use has recently stopped.

When testing a hair sample for long-term alcohol use, a laboratory will look for one of two different alcohol markers: Ethyl Glucuronide (EtG) or a fatty acid ethyl ester (FAEE) called Ethyl Palmitate (EtPa). EtG is produced by the liver and deposited into the hair through sweat. EtPa is produced in the blood and incorporated into hair via sebum, EtPa can also be elevated when using hair products containing ethanol.

What can segmentation testing tell us?

Courts will often request analysis of your client’s pattern of consumption and an assessment of whether use has increased or decreased over a period of detection.

By segmenting the hair into monthly sections (1cm of hair is representative of an average of one month of growth), laboratories can provide a more comprehensive assessment of the pattern of change and it is possible to gain a detailed chronological history of drug or alcohol use.

Segmentation can be used to detect drug and alcohol markers in hair between seven days and six months after use. Segmentation can therefore provide a more accurate assessment of the person’s substance misuse or abstinence from drugs or alcohol when presented to court, and potentially support the person’s declaration of either reducing the use of a drug or even cessation.

The key benefits of segmented hair testing:

  • Gives a more accurate assessment of a client’s substance misuse or abstinence.
  • Can help show whether the client is making attempts to stop misuse.
  • Shows when someone’s addiction is increasing.

Whilst the use of segmentation can help build this picture, it cannot be used to determine when exactly drugs were used i.e. on what day of the week or weekends as opposed to weekdays, as it is an integrated average result of each section tested. Similar with alcohol, it cannot be used to identify if a person is consuming alcohol throughout the week or if they are binge drinking on weekends only.

Debunking misinformation about segmented alcohol testing

Many laboratories do not advise the segmentation of hair samples for alcohol, citing guidelines provided by Society of Hair Testing (SoHT) and claiming that segmenting hair samples for alcohol testing is not recommended.

This is not accurate.

In fact, SoHT guidelines from the 2016 and 2019 SoHT census both state that segmentation for alcohol analysis may provide additional information, particularly in cases where someone has drastically decreased their alcohol consumption or is trying to prove abstinence.

However, the SoHT does advise caution when interpreting results of segmented analysis and recommends that the hair sample is no shorter than 3cm and no longer than 6cm in length. This is because EtG will increase in hair sections closer to the scalp and EtPa will increase in hair sections further from the scalp. We know that the levels of EtG decrease with normal hygiene practices, such as showering, due to the wash out effect. At Cansford, we have analysed many samples, and can provide insight, even at levels of 0-3cm. We describe some of the work we have done to support this later in this article.

We regularly show that segmented analysis of hair for alcohol markers can have a significant and helpful result when the client has allowed us to state that this is in line with their declaration. For instance, when clients have drastically reduced or abstained at a specific time. In such a case, we can expect to see a low level of EtG in a very recently cut hair sample (1cm, which represents approximately one month of hair growth).

Supporting our claims

Our scientists have studied the results of over 3,000 samples that were segmented into 3cm by 1cm sections and found that segmentation was valuable and pertinent in those cases where people needed to show that they consistently cut down alcohol use over the period. 

To explain the results, a short explanation of reporting guidelines for EtG in hair may be useful. A finding of less that 5pg/mg of EtG in a hair sample is suggestive of abstinence, levels of 5pg/mg to 29pg/mg consistent with alcohol consumption, but not at a chronic excessive level and levels greater than 30pg/mg suggests chronic excessive alcohol consumption.

A small but significant number of the 3,000 samples we tested showed abstinence more recently with an average of 10pg/mg for segment 1-2cm and 16pg/mg for segment 2-3cm. For these cases the average 0-3cm was 8.7pg/mg. Therefore, we could inform our clients that these people were significantly decreasing their alcohol intake.

In addition, a number of cases showed the same pattern when the average EtG was 77 pg/mg for the three segmented hair sections. We could state, with confidence, that the clients were successfully decreasing alcohol use.

When decisions are being made in court that can have a huge impact on children and families’ futures, getting it right is vital. As a laboratory, it is our aim to debunk misinformation around segmentation testing for alcohol use and continue to provide evidence to demonstrate its value in supporting family law cases.

For more information from Cansford Laboratories about hair strand drug and alcohol testing, visit

This article was submitted to be published by Cansford Laboratories as part of their advertising agreement with Today’s Family Lawyer. The views expressed in this article are those of the submitter and not those of Today’s Family Lawyer.

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