Site Overlay

How Far Back Does Hair Drug Testing Go?

At Lextox, we undertake hair testing for drugs and substances of abuse. We then produce legally defensible results with an interpretation as an expert report accepted in every UK family court. A question often asked about our testing is how far back does hair drug testing go?

Human hair grows at an average rate of 1cm per month. Therefore, a 3cm section of scalp hair can provide an approximate three-month retrospective drug use profile. We can use consecutive sections of hair, typically 1cm or 3cm, to profile longer periods.

When a drug enters the human body, it is transported via the bloodstream and incorporated into the hair follicle. As the hair grows,  trace amounts of drugs are trapped within the hair shaft. Often, many people are surprised by the answer to “how far back does hair drug testing go?” and, as such, can be caught out by the results. The simple answer is hair drug testing can go back as far as the hair shaft is long. So, if a 3cm section of hair provides an approximate 3-month overview, a 12 cm section of hair can offer an approximate 12-month profile.

Hair drug testing can test for drugs and substances such as Benzodiazepines, Cannabis, Cocaine (incl. Crack Cocaine), Ecstasy (MDMA), Ketamine, Mephedrone (M-Cat), Methadone, Methamphetamine (incl. Amphetamine), and Opiates (incl. Heroin).

A metabolite is a substance produced by the body when a drug is ingested and can be used to show direct usage. Our team analyses hair samples to detect trace amounts of drugs and their metabolites. From our laboratory analysis, we can provide an expert interpretation of the levels of drugs detected.

Month-by-Month Analysis

A month by month analysis can break down a scalp hair sample into monthly sections, showing individual results for each month. To do this, our team segments hair samples into 1cm sections (the approximate monthly growth), allowing us to see a monthly drug use profile. This segmental analysis can help show any trends, such as an increase or decrease in the level of drug detected, and can also help to highlight low-level instances.

Overview Analysis

An overview analysis covers a three-month period with a 3cm section of scalp hair and will identify drug use within those approximate three months. We can use consecutive segments of either 1cm (1 month) or 3cm (3 months) to assess drugs detected for as long as the hair is. For example, we can use a 12cm hair sample to profile approximately 12 months of drug and substance use.

In conclusion, the answer to “How far back does hair drug testing go?” is that there is no limit. We can test approximately one month of drug use for every centimetre cm of hair. If you want to know more about hair testing for drugs and substances of abuse, get in touch with our team today by calling 029 2048 4141 or email [email protected], and someone will get in touch as soon as possible.

Published 06/09/22 – All information correct at time of publication