Kristof Pil

Current developments in drug testing in oral fluid.

In the last few years, significant developments have occurred on the key issues involved in oral fluid drug testing. New pharmacokinetic studies have been conducted, optimal cutoffs have been proposed, and new studies have examined the correlation between oral fluid drug concentrations and impairment. Recent studies (eg, the discovery of the presence of THC-COOH in oral fluid) can contribute to solve the issue of false-positive results caused by passive exposure to marijuana. Reliable point-of-care drug testing is still problematic, especially for cannabinoids and benzodiazepines. To date, there is no device that allows both reliable and practical point-of-care testing. The importance of liquid chromatography- tandem mass spectrometry in confirmation analysis has increased over the last several years. It can be expected that this trend will continue because the low sample volumes make simultaneous detection of different drug classes with limited sample preparation necessary. Literature on proficiency testing to ensure reliability and comparability of results is limited. Oral fluid has become an important sample type in driving under the influence research, and the first legal random drug testing program in oral fluid since 2004 has been organized in Victoria. It can be expected that the role of oral fluid as an alternative matrix will keep increasing in the future.

An analytical evaluation of eight on-site oral fluid drug screening devices using laboratory confirmation results from oral fluid

The performance of eight on-site oral fluid drug screening devices was studied in Belgium, Finland and the Netherlands as a part of the EU-project DRUID. The main objective of the study was to evaluate the reliability of the devices for testing drivers suspected of driving under the influence of drugs (DUID). The performance of the devices was assessed by their ability to detect substances using cut-offs which were set at sufficiently low levels to allow optimal detection of positive DUID cases. The devices were evaluated for the detection of amphetamine(s), cannabis, cocaine, opiates and benzodiazepines when the relevant test was incorporated. Methamphetamine, MDMA and PCP tests that were included in some devices were not evaluated since there were too few positive samples. The device results were compared with confirmation analysis results in oral fluid. The opiates tests appeared to perform relatively well with sensitivity results between 69 and 90%. Amphetamines and benzodiazepines tests had lower sensitivity, although the DrugWipe test evaluated was promising for amphetamine. In particular, it is evident that the cannabis and cocaine tests of the devices still lack sensitivity, although further testing of the cocaine tests is desirable due to the low prevalence and low concentrations encountered in this study.

Analytical Evaluation of Four On-Site Oral Fluid Drug Testing Devices

The use of oral fluid (OF) as an alternative matrix for the detection of drugs of abuse has increased over the last decade, leading to the need for a rapid, simple, and reliable on-site OF testing device. Four on-site OF drug testing devices (Dräger DrugTest 5000, Cozart DDS, Mavand Rapid STAT, and Innovacon OrAlert) were evaluated on 408 volunteers at drug treatment centers. UPLC-MS-MS results were used as reference to determine sensitivity, specificity and accuracy for each device, applying Belgian legal confirmation cutoffs for benzoylecgonine, cocaine, and THC (10 ng/mL); morphine and 6-acetylmorphine (5 ng/mL); and amphetamine and 3,4-methylenedioxymethylamphetamine (25 ng/mL). Sensitivity for cocaine was 50%, 50%, 27%, and 11% for DrugTest, OrAlert, Rapid STAT, and DDS 806, respectively. For opiates, sensitivities were 84%, 73%, 77%, and 65%, respectively. For THC, the sensitivities were 81%, 23%, 43%, and 28%, respectively. For amphetamines, the sensitivities were 75%, 33%, 17%, and 67%, respectively. Specificity was >88% for opiates and THC, > 90% for amphetamines, and > 97% for cocaine. All tests showed good specificity. DrugTest had the highest sensitivity, although it was still low for some analytes.

Quantitative analysis of adenosine using liquid chromatography/atmospheric pressure chemical ionization-tandem mass spectrometry (LC/APCI-MS/MS)

Adenosine-secreting cellular brain implants constitute a promising therapeutic approach for the treatment of epilepsy. To engineer neural stem cells for therapeutic adenosine delivery, a reliable and fast analytical method is necessary to quantify cell-based adenosine release. Here we describe the development, optimization and validation of adenosine measurement using liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry (LC-APCI-MS/MS). LC-MS/MS in positive ion mode used selected reaction monitoring at m/z of 268.2/136.1 and 302.2/170.0 for adenosine and the internal standard, respectively. The bias was within 15% of the nominal value and evaluation of precision showed a relative standard deviation lower than 15% for all measured concentrations. The lower limit of quantification of adenosine was 15.6 ng/ml. Freeze and thaw stability and processed sample stability also fulfilled the acceptance criteria. Evaluation of the matrix effect showed that the method is not affected by relative matrix effects. The major advantages of this method are the absence of an extraction phase and the combination of the high selectivity and sensitivity characteristic for the LC-MS/MS technique, with a short run time of 4.5 min. These results demonstrate that this method is a useful tool to measure adenosine concentrations in culture medium released from stem cells in vitro.

External quality assessment of multi-analyte chromatographic methods in oral fluid

BACKGROUND A proficiency testing scheme was set up for the DRUID (Driving under the influence of Drugs, Alcohol and Medicines) research project, funded by the European Commission, in which oral fluid is analysed by eleven laboratories. A common collection and analysis methodology is used: Statsure Saliva Sampler is used for collection and LC-MS/MS or GC-MS confirmation analysis of 22 substances is performed on all samples. Despite internal validation and quality control samples, external quality assessment is still necessary to further increase comparability of results. Four rounds of proficiency testing (PT) were organized between March 2008 and September 2009. METHODS Qualitative results were evaluated using sensitivity and specificity. Quantitative results were evaluated using z-scores and the standard deviation of Horwitz. RESULTS Specificity was above 99% in each round, sensitivity per analyte varied between 81.7 and 100%, and 20 out of 22 analytes had a sensitivity above 90%. The percentage of satisfactory z-scores increased from 79.4% to 89.2%. This trend was seen for all drug classes, except zopiclone. Results were discussed with participating laboratories and problems were addressed. CONCLUSIONS Because of these corrective actions, DRUID laboratories have a lower variation in results than previously published PT schemes in oral fluid.