Understanding Reporting Cut-off Levels

In the past, we have been asked by clients for more information on our reporting cut-off levels, namely what they are and their significance to hair drug and alcohol results.

This blog aims to answer these questions and explain the importance of cut-off levels.

Important definitions:

Reporting cut-off level – The level used to determine if an analyte is detected or non-detected.

Detected – A level that falls on or above our reporting cut-off level.

Non-detected – A level that falls below our reporting cut-off level.

The reporting cut-off levels differ depending on the drug that is being analysed. The Society of Hair Testing (SoHT) recommends cut-off levels for alcohol markers and drugs to indicate chronic (repeated) use. Lextox applies these cut-off levels as the reporting cut-off level where applicable.

The levels that Lextox apply (as recommended by the SoHT) are used to identify chronic (repeated) use of a drug. One off instances of drug use are unlikely to give rise to positive results as insufficient drug/metabolite would be expected to accumulate in the hair to be detected above the reporting cut-off levels.

In the case of a detected result, the levels of drug detected in the hair are best used as a guide to the changes in use by the individual and not to the quantity of drug consumed.  This is because there are many factors that influence the amount of drugs in hair such as the purity of the drug consumed, and individual variations in drug metabolism and drug incorporation rates into hair.

The hair alcohol test should be used to determine chronic excessive alcohol use; it is not a test to determine social drinking or binge drinking. This is because the results obtained are average results for the whole approximate time period, and reflect alcohol use at any time within the tested time period covered by the hair analysis.

SoHT guidelines were acknowledged as the current industry standard for hair drug and alcohol testing during a 2017 family law case involving The Honourable Justice Peter Jackson. Lextox has always followed these guidelines and our Experts attend annual meetings to contribute to them as members of the SoHT. During this case Mr Justice Peter Jackson also provided a number of suggestions for hair testing organisations working in family law. Many of these were and continue to be employed by Lextox in its existing practices.

If you would like any more information please contact us at [email protected] or 029 2048 4141.