Impact of DBS sampling site (fingertip vs. upper arm) on the concentrations of ephedrine

Code: DBS20AS7JM

The minimally invasive dried blood spot (DBS) technique has the potential to improve the time-and-cost efficiency compared to traditional matrices in doping control. The potential impact of the sampling site e.g. finger vs. arm on the concentration of target analytes needs to be established, especially when analyzing for threshold substances prohibited in-competition only. Eight healthy male volunteers will receive a single oral administration of ~20 mg (‘low dosage’) and 60 mg (‘high dosage’) of ephedrine in a randomized crossover design with one week between the interventions. Parallel DBS samples from the fingertip and upper arm will be collected at 0 (pre-administration control sample), 1, 2, 4, 6 and 8 hours post-administration. From the DBS samples the ephedrine concentration will be determined. Additionally, venous blood samples will be collected through a peripheral venous catheter on the same time points to compare the DBS concentrations of ephedrine with those in plasma.

Main Findings

Dried blood spot (DBS) testing allows for fast, easy, and minimally invasive collection of microvolumes of blood. In an anti-doping context, DBS testing has particularly relevance for substances prohibited in-competition only, as it can determine the presence of pharmacologically relevant blood concentrations during the in-competition period. A wide range of collection methods and devices exist for DBS collection allowing collection of capillary blood from different anatomical sites, but the possibility to use different devices in an anti-doping setting would rely on agreement in substance concentrations between sampling sites and between devices. Furthermore, it is of interest to evaluate the agreement between concentrations of target analytes in DBS and conventional venous plasma samples. Herein, we collected matched upper-arm DBS, finger prick DBS and venous plasma samples from 8 healthy, male subjects in an 8-hour period following oral administrations of 20 mg (‘low dose’) and 60 mg (‘high dose’) of ephedrine. We observed no consistent trend in the dependence of ephedrine concentration on blood sampling site or sampling device, and the correlations between ephedrine concentrations in finger prick DBS and upper-arm DBS were very high (Pearson’s r > 0.80) after both low and high dose administration. These results indicate that DBS originating from finger prick and automated upper-arm collection, along with conventional venous blood samples, can be used for quantification of ephedrine in doping control.