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When it comes to family law cases, accurate (and rapid) testing is often relied upon to help decision making. Cases may involve one or both parents with substance abuse issues. As such, it is important to understand the level and pattern of drug and/or alcohol misuse to help assess any risk to dependents. Children may ultimately need moving to a place of safety. Alternatively, treatment for dependence issues could be initiated to hopefully reduce the impact on the family unit.

Hair strand testing (known as HST) is routinely used in the forensic and family law fields and is considered the gold standard for providing a history of drug or alcohol abuse. Head hair grows at an average rate of 1 cm each month; therefore, drug or alcohol use can be established over a defined period depending on the length of hair selected. However, the accuracy of any hair analysis depends on both the sampling procedure and the laboratory techniques employed. AlphaBiolabs is accredited by UKAS, to the quality technical standard of ISO 17025, and we are also certified to ISO 9001. We also adhere to the Society of Hair Testing (SoHT) guidelines for drug and alcohol testing in hair and follow their recommended cut-off levels [1].

Hair strand testing (HST) for drugs

Following consumption of a drug and its passage into the bloodstream, a proportion of the drug’s metabolites will enter the hair follicle. Drug use can therefore be established over a defined period.

There are two types of head hair strand tests available: overview or segmented analysis.

In an overview test, any episodes of drug taking are averaged out over the period being tested. Overview analysis can therefore provide a general indication of drug use. This could range from 3 cm to identify drug use within that 3-month time period, up to 6 or even 12 months, dependent on the length of hair available.

Segmented analysis provides a more detailed analysis and the episode of drug taking can be pinpointed to the actual month. In a 6-month segmented analysis, hair samples are sectioned into six segments of 1 cm to provide six individual monthly analyses. Segmented analysis is therefore especially useful if you need to obtain a trend in drug use, such as to see a decrease or increase, or to highlight intermittent use.

Hair strand testing (HST) for alcohol

Unlike hair strand drug testing where the metabolites are absorbed through the root of the hair, when an individual consumes alcohol the markers are found along the entire length of the hair. Therefore, it is not possible perform segmented analysis.

A history of alcohol consumption is achieved by looking at two metabolites of alcohol in head hair: ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEEs). These alcohol biomarkers are absorbed into the hair via different routes and their levels can assist in assessing excessive alcohol consumption. Both markers are analysed because they are affected by external factors in different ways. EtG is incorporated into the hair mainly through sweat and is water soluble. As such, some EtG may be lost through the use of hair dye and excessive hair washing.

FAEEs are incorporated into hair via sebum and are lipophilic. These biomarkers are not affected by hair washing, but the amount detected could be affected by use of alcohol-containing hairsprays, gels and wax.

Because of the respective strengths and weaknesses, both EtG and FAEE tests should be performed and their findings should support each other in order to determine chronic excessive consumption of alcohol.

The level of biomarker found in the hair can help determine if a person has been drinking chronically and excessively, and will show either a 3- or 6-month overview.

Getting a sample

Hair strand samples are normally collected by a qualified nurse or trained sample collector. The samples need to be cut from the highest point of the scalp (the vertex) and need to contain around 200 individual strands (about the width of a pencil). Ideally, it should be taken from a discrete area.

If head hair is not available for a drugs test, alternative collection sites could be considered including pubic, underarm, chest, leg and beard hair. The growth rate of hair from these alternate sites differs from head hair and as such body hair cannot be used to determine a specific timeframe of drug use.

Head hair is preferred for alcohol testing, but some types of body hair can also be analysed. However, it is only possible to perform EtG analysis on hair samples collected from the chest, arm, leg and beard. The timeframe for body hair alcohol testing is also more approximate due to the nature of this hair growth and can only be determined when the hair length has been measured.

AlphaBiolabs has a network of trained sample collectors able to take hair strand samples for free at its nationwide Walk in Centres. For expert advice on hair strand drug testing and hair strand alcohol testing, please call 0333 600 1300 or email us at info@alphabiolabs.com

[1] http://www.soht.org/component/content/article/9-nicht-kategorisiert/85-statement-2011