Drug Facilitated Crimes Series – Analytical Considerations Part 3.
When it comes to drug testing in drug facilitated crimes, there are factors within the laboratories and testing procedures that directly influence the outcome and findings of the level of effect that the drug may have had. These factors are outlined here, to significantly show how many levels there are to discovery of an accurate result. The manner in which metabolites and parent drugs are tested for, measured, and results recorded will have a direct effect on further findings.
Certified Reference Materials (CRMs)
Use of certified reference materials are helpful to ensure accuracy and relevance of amounts recorded. If these are not available, commercial reference standards are a cost effective alternative, but do not provide formal traceability. Because of the potential consequences of the results, these are necessary inclusions for quality assurance. CRMs are there for the traceability of the substance and reliability of the test.
Each drug (listed as a DFSA) has a set maximum limit that should be tested for. Where possible, a lab should test for lower levels as well.
Minimum Required Performance Limits (MRPLs)
It is necessary to ensure that all laboratories involved in the case know what standards and methods are being used to test for substances. Make sure that all the laboratories are assigning to a minimum required performance limit. This will ensure that the standard of the testing is above a certain level. These limits must be complied with by all laboratories testing for DFSA related substances. This is not to suggest that false results are impossible when the limits are applied, nor that positive results are impossible with laboratories making use of methods that fall short of the limits – merely that it ensures a standard of accuracy within the lab that can be more reliant within the use of results to serve justice.
Factors that fall to the Laboratory
A lab must employ methods of quality control, and state these in their records, to ensure validity of its findings. The use of CRMs and MRPLs assist in this regard. This is not something that falls into the hands of the person running the tests (toxicologist) and is the direct responsibility of the lab and its documentation, transport, and storage methods.
Another factor that influences the findings of the effect of DFSAs on an incident is the volume of the sample – the person taking the sample should be aware of the reasons for the sample in order to ensure that a sufficient sample is being taken – that sufficient test can be run, or re-testing can take place – and enough for all laboratories to have access to a portion of the sample taken.
Record should be made of storage conditions of any facility where samples are stored, and the length of time for which they have been stored should also be evident. Communication lines being open, thorough, and timeous also allows for accurate result reporting – to lessen any confusion or loss of data, it is better that all parties have immediate access to results and have them placed on record. In turn, these results should match up.
Staff Skills
Aside from well-equipped laboratories, staff should also have specialty skills, including knowledge of chromatography-mass spectrometry, and background in drug metabolism and pharmacokinetics over and above clinical and forensic toxicology, pharmacology. Their ability to handle and record data, interact with investigative teams, and ensure human dignity is essential.
Testing and recording should be directed to labs that are equipped to meet the standards outlined above, as well as take place at a local level, to ensure accuracy of results.
The content of this article is provided by Connectica, LLC and has not been reviewed by a toxicology expert witness.
