Drugs of abuse analysis: are Dried Blood Spots suitable for "on street" controls?

Driving under the influence (DUI) of psychotropic substances, such as drugs of abuse (DoA) and/or alcohol, is one of the leading causes of traffic collisions. Furthermore, car accidents are the first cause of death (and of acquired disability) for young people under the age of 35. As a consequence, roadside controls are routinely performed by law enforcement agencies as part of prevention/dissuasion policies. Within this framework, the correct and timely sampling of a significant biological matrix, followed by a reliable qualitative/quantitative analysis, is the cornerstone of a fair assessment of the DUI state. For alcohol intake, the use of breathalizers has reached a satisfactory level of reliability and speed. However, assessing the actual state of drug intoxication is much more complicated. It is important to have at disposal fast and reliable analytical methods, able to provide good results for the identification and the quantitation of the most important DoA. The Laboratory of Pharmaco-Toxicological Analysis develops advanced methods for the analysis of DoA in different biological fluids and tissues, in particular in an innovative matrix: Dried Blood Spots (DBS). DBS are obtained from blood drops collected on filter paper from a simple finger prick; the technique represents a very attractive and feasible alternative to the traditional blood sampling. It is especially useful “on street”, because is minimally invasive and allows sample collection, transport and storage, granting good stability without requiring refrigeration nor other pre-treatments. A few original analytical methods are for the analysis of different DoA in human DBS, for the purpose of reliable “on street” drug testing.The methods are based on LC-ESI-MS/MS (triple quadrupole) and samples are directly injected into the system, after a very fast solvent extraction. The results obtained until now on cocaine, cannabinoids and their main metabolites are promising, in terms of extraction yields, sensitivity and selectivity. Assays are in progress in order to fully validate the methods.