Athletes’ feedback and impact of DBS sampling site (fingertip vs. upper arm) on the concentrations of endogenous testosterone

Code: DBS20CT34JM

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. Understanding the athletes’ preferred sampling site will support the drafting of WADA Collection Guidelines/ISTI in the implementation process. Furthermore, the potential impact of the sampling site e.g. finger vs. arm on the concentration of target analytes needs to be established. Doping Control Officers (DCOs) will collect capillary blood from the finger (finger-prick) and from the upper arm (specific collection device) from 108 athletes (males and females) of various sport disciplines. The DCOs will record the time needed to collect the samples, register the number of unsuccessful attempts and evaluate the usability of the collection devices and whether they prefer the collection of DBS from the fingertip or the upper arm. The athletes will fill out a questionnaire regarding the perception and painfulness of the two DBS collections and whether the collections processes have had any impact on their sport activities afterwards. The lab staff will to fill out a questionnaire once they have received the samples to understand the suitability of the samples for analysis. The DBS samples will be analysed for the concentration of endogenous testosterone.

Main findings

Currently several DBS collection devices exists allowing collection of capillary blood from different anatomical sites. Nevertheless, the suitability for collecting DBS samples in an anti-doping context depends on the sample collection experience by the athletes, doping control officers (DCO) and the handling of the sample by the laboratory staff. Furthermore, agreement between quantitative measurements is important if more than one collection method (device and/or sampling site) is approved. In this project, a total of 108 matched DBS samples from the fingertip (HemaSpot HF; lancet device) and the upper arm (Tasso-M20; microneedle device) were collected from 49 female and 59 male national level athletes from various sports (handball, weightlifting, football, running and wheelchair rugby). Following sampling, the collection process was evaluated by athletes and DCOs. Furthermore, upon reception of the samples, the laboratory staff compared the quality and usability of the samples from the two devices. The testosterone concentration was measured in all samples and the correlation between concentrations determined.

Overall, the DBS sampling was associated with minimal sensation of pain and a high general experience by the athletes, but the perceived pain was rated lower (-0.4 ± 1.6, p < 0.05) and the general experience rated higher (+0.6 ± 2.3, p < 0.001) during upper-arm DBS collection than during DBS collection from the fingertip. Likewise, the DCOs rated the general experience with the upper-arm DBS collection higher (+1.6 ± 1.1, p < 0.01) than the fingerprick DBS collection, partly due to problems occurring more frequently during the DBS collection from the fingertip (28% of collections) than from the upper arm (6% of collections). Both procedures were equally fast, lasting only around two minutes on average, which is a great advantage compared to urine. When choosing, the great majority of DCOs and athletes, independent of gender and discipline, preferred the automated DBS collection from the upper arm over the manual collection from the fingertip, and both DBS collections over conventional sample collection methods (urine and venous blood collection).

Both devices provided easy access to the DBS sample and the overall analysis time was not affected by the choice of DBS material, however, the Tasso-M20 device was the preferred device amongst the four analysts preparing the samples due to less sample handling prior to sample preparation. Endogenous testosterone was quantified in DBS samples from both devices with good repeatability (RSD < 5%) and reproducibility (RSD < 10%). The quantitative analyses showed good correlation between samples collected from the fingertip and the upper arm from athletes (r = 0.921, p<0.0001), as well as non-significant difference of the median testosterone concentrations (1.70 ng/mL for Tasso and 1.67 ng/mL for HemaSpot, p = 0.503). A small, measured bias between Tasso and HemaSpot (-7.45%) was observed, likely due to unsatisfactory volume control in the HemaSpot compared to the Tasso device. Collectively, the results suggest that there is no physiological difference in the basal testosterone concentrations in capillary blood samples collected from the fingertip and the upper arm.

In conclusion, both an automated upper-arm DBS collection device [Tasso-M20] and a manual fingerprick DBS system [HemaSpot HF] could be used for DBS collection in an anti-doping setting. However, for subsequent quantitative analyses, the volumetric control of the Tasso-M20 spots seemed more robust than for HemaSpot HF. Both DCOs and laboratory personnel seem to prefer the upper-arm DBS collection with the Tasso-M20 device. If more than one collection method (device and/or sampling site) is approved, it appears crucial that the analytical assays are validated and calibrated on the respective DBS-devices/materials.