Bernd Huppertz1*, Michael Bottcher2, Stefan Lierheimer2, Prisca Gottwald3, Sergej Bleicher4 and Martin Schafer3
Background: For many years, drug of abuse analysis was typically performed on urine using enzyme immunoassays with Gas Chromatography–Mass Spectrometry (GCMS) confirmation. However, analytical instruments improved significantly over the last decades, allowing analysis of smaller sample volumes and other matrices, such as capillary blood and oral fluid, with lower drug concentrations. To our knowledge, the present study is the first to compare the matrices urine, capillary blood and oral fluid using similar analytical techniques and paired samples.
Method: Samples were collected from patients admitted for detoxification to Huyssens-Stiftung, Essen, Germany over a period of maximum 14 days. Each patient provided samples of all three matrices at almost the same time during each collection cycle. All analyses were performed with Liquid Chromatography with tandem Mass Spectrometry (LCMS/MS).
Results: Detection periods vary between the matrices depending on the analytes and several positiv results in one matrix could not be confirmed in one or two of the others. In particular capillary blood showed some implausible results.
Conclusion: It depends on the formulation of the question which of the matrices is better suitable for any given purpose. The highest positive rates, for example, for 6-Monoacetylmorphine (6-MAM) can be found in oral fluid, and the longest detection periods for cannabis and benzodiazepine detection can be found in urine. Although, again depending on the formulation of the question, the very long detection periods may make it advisable to use a cut off for urine in the range of 10 to 50 ng/ml, depending on the analyte.
Ethical approval: The study was authorized by the ethics commission of the Medical Faculty, University of Duisburg-Essen/Germany on July 15th, 2016