Drug Driving – Checking blood results

Drug Driving – Checking blood results

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Drug Driving – exceeding the prescribed limit

Have you been charged with drug driving under s.5A Road Traffic Act 1988? If so, it is important to remember that driving with THC, cocaine, MDMA or any other drug in your body is NOT illegal. It may, however, be illegal if those drugs exceed the prescribed limit.

Considering this, it is imperative the police not only identify the precise drug in your body, but also accurately quantify the exact concentration of that substance – to prove you are over the drug drive limit.

The police ‘employ’ forensic laboratories to analyse blood samples taken at the police station. These labs use a measurement technique called ‘Gas/liquid Chromatography-Mass Spectrometry’ (G/LC-MS) to both identify the drug and quantify the specific concentration of that drug in your blood.

To accurately measure the quantity of the unknown drug, the lab will compare your blood specimen to a pre-prepared standard sample of a known  concentration. In effect, the GC-MS device will be calibrated with a known concentrations of THC, cocaine, MDMA, etc to compare to the unknown specimen of blood. Therefore, if the GC-MS device is not correctly calibrated with the standard of a known concentration it will not be able to accurately analyse your blood sample.

How the police can get it wrong

In a recent drug drive case handled by M.A.J. Law Solicitors, our client was pulled over by the police at the roadside. Using a roadside drug screening device our client tested positive for THC and was subsequently arrested. 2 hours and 14 minutes later, a blood sample was taken at the police station by a healthcare professional and this was later sent to the forensic lab for analysis. The sample was then analysed and found to contain ‘no less than 2.8ug/L of THC’. This exceeding the legal limit of 2.0ug/L.

Specialist solicitor Conor Johnstone, of M.A.J. Law Solicitors, requested from the CPS all relevant forensic evidence including the detailed Forensic Report 2 and full analytical data pack. Note that the police / CPS routinely only supply a very basic two page Forensic Report (known as an SFR1) when anyone is charged with drug driving. The more detailed Forensic Report (known as an SFR2) consists of some 12 pages and the full analytical data pack averages 80 pages.

It is very important that your solicitor has access to the same material / evidence that has been produced by the forensic lab. If you only ever see the basic SFR1 report you will never succeed in challenging the accuracy of the result.

Once Conor Johnstone obtained the full evidential data from the forensic lab, this was then sent to one of our expert witnesses for review. The expert witness we used was a leading scientist with particular expertise in the analysis of blood specimens using the GC-MS technique. Upon examination of the documentation supplied by the police forensic lab, our expert identified numerous failings by the forensic lab.

Our expert found the integrity of the sample was not established, nor was there recorded evidence of its correct storage or treatment. Importantly, when looking at the data from GC-MS analysis, our expert found only half of the required quantity of the internal standard of a known concentration was used for calibration of the GC-MS device. In effect, this resulted in a doubling in the concentration of our client’s identified THC sample.

Our client was charged with being over the drug drive limit because the forensic lab reported his result as ‘no less than 2.8ug/L of THC’. However, as the result had, in effect, been falsely increased by the lab by 100%, our client’s true reading was 1.4ug/L, this placing him under the legal limit of 2ug/L.

This case clearly highlights the importance of challenging any evidence provided to you from the forensic lab, the police to the CPS. At M.A.J. Law Solicitors we offer a free initial telephone consultation where we can discuss your case in confidence. If we take on your case, we can usually offer a fixed fee to cover our legal defence and any appearance in court. Contact Conor Johnstone on 0151 422 8020.

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