Overview vs. Segmented Hair AnalysisThere are two types of hair drug tests available: overview or segmented analysis.
What drugs can be detected?
The standard drugs we test for in head hair are:
- Ecstasy (MDMA)
- Phencyclidine (PCP)
Types of analysis
An overview analysis is beneficial to obtain 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 (2 x 3) or even 12 (4 x 3) months, dependent on the length of hair available. A 6-month overview could also be used to provide two results: one for the earlier 3 months and a second result for the later 3 months. If a more detailed analysis is needed, segmented would be the preferred option.
By segmenting head hair samples into monthly 1 cm sections, a month-by-month profile of drug use can be attained to provide a detailed historical profile of an individual’s drug exposure.
In an overview test, any episodes of drug taking are averaged out over the period being tested. For example, if an individual has not taken drugs for 2 months but then takes an excessive amount in the next month, drug markers will be found along the entire length of the hair. In the case of segmentation, the episode of drug taking can be pinpointed to the actual month.
Which test should you choose?
Answering the questions of When and How often your client used a substance can make or break a family law case. It is therefore essential to choose a test method that is right for your case.
If a 3-month overview drugs of abuse test is selected, even if an individual uses drugs occasionally, the test may come back positive for the whole 3-month period. This result implies that the sample donor had been abusing drugs during the whole period analysed.
To overcome this, segmented hair drug testing could be performed over the same 3-month period. The sample donor could show positive one month and negative the other 2 months. This would provide a more accurate assessment of the individual’s drug abuse/abstinence when presented to the court for scrutiny.
Cases such as this demonstrate the importance of an expert advising on the appropriate test to use. Taking an average of drug levels in a specified hair section without the knowledge of levels in the hair section prior to the period of interest can produce misleading results.
Examples of the head hair analyses regularly performed
|Analysis type required||Number of segments||Reported time period||Type of Test|
|3 months||1||3 months||Overview|
|3 months||3||3 individual months||Segmented|
|6 months||2||2 x 3-month periods||Overview|
|6 months||6||6 individual months||Segmented|
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Last reviewed: 05/10/2023
We explore hair drug testing, how it works, and whether there are external factors that could affect the hair drug test result.
In this article, we look at body hair versus head hair drug tests and highlight the differences between the two.