Conflicting drug test results: what next?

Drug testing always provides black and white answers. 

It’s a fair assumption to make - but it’s not always the case. 

It’s perfectly possible for the same individual to undergo two different types of drug testing - hair and urine, for example, and for the two tests to return two very different results.

In the context of the family law court, this can be incredibly confusing - and can impact the results of vital family cases. So, what happens when different tests return conflicting results about the same individual?

Why is there variation in drug testing results?

Drug test results can vary for two key reasons. The first is that different labs may have different testing processes - which is why it’s so important to choose a drug testing laboratory with the appropriate accreditation.

The second is that different drug and alcohol testing methods can return very different results - the potential variation can be enormous. A positive urine result will not necessarily mean that a hair test result from the same subject will be positive, and vice versa. 

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In situations like these, the party who ordered the test may choose to go to a different lab, test with a sample of a different type (oral fluid, for example), and get a different result yet again, adding further to the confusion. While all of the conflicting tests could be put together as a story with both sense and value, this isn’t an easy task without a vast amount of training and experience.  

In situations where conflicting test results occur, the key is in understanding the nuances of the testing methods involved, allowing you to explain the results accurately and in context.

Hair testing

In hair drug testing, there are two key factors that could lead to different labs returning different test results for the same subject. 

The first is variation in how the sample is collected. Different labs will choose to collect samples in different ways - and while two differing methods may both be “by the book”, they can return varying results. 

The second is variation in hair growth. Hair falls into three different growth phases - and the amount of each sample accounted for by each type may vary on collection. 

The important thing is that both of these factors are taken into account when analysing samples, enabling the results to stand up in court - in hair testing, context is everything. Find out more about variation in hair results.

Urine testing

Urine testing is a commonly chosen drug testing method in family law, due to its affordability, its speed and its relative lack of invasiveness. However, it is important to note that there are various factors that could lead to conflicting results. 

Excessive water consumption by the subject can dilute the concentration of a drug in a sample, while it may also be possible for subjects to switch their sample or dilute it once produced, due to the privacy required for the sample to be collected. 

In addition, it could be that an individual’s urine pH is altered by either food or medication between the two samples being taken. See more on how urine testing results can vary.

PEth testing

At Cansford Labs we now offer PEth testing, a finger prick test that reveals levels of alcohol use over up to a four-week period. These tests are incredibly accurate in determining alcohol use over a 3-4 week timeframe - but there is still the potential for two different labs to return different results. 

Any variation in results is likely to be down to the specific cut-offs that each individual laboratory uses. If a sample tests positive at one laboratory but not at another, it may be that the first lab works to lower cut-off levels - meaning a greater likelihood that smaller concentrations of alcohol will be detected. Read more on PEth alcohol testing here.

Context is key

Interpreting drug and alcohol test results can be complex - which is why reporting is best left to your chosen testing partner. These tests are best seen as indicators of an individual’s drug or alcohol use, and context is everything, as the above shows. 

Rather than simply looking at a single figure and reporting a black or white answer, it is more beneficial to family lawyers to look at how test results have varied over a period of time. It may be that an individual is still misusing a substance, but that usage has decreased over time - or vice versa. By understanding the context in which samples are taken and results analysed, though, it can be easy to explain why two different labs can provide two very different sets of results for the same subject. 

To learn more about your choices when it comes to accurate drug testing methods, get in touch. 

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