Assessment of DBS stability during transport and long term storage

Code: DBS20AS1AT

Due to the aimed implementation of dried blood spot (DBS) sampling in doping controls for the upcoming Olympic events (Summer Olympic / Paralympic Games 2020 in Tokyo and Winter Olympic / Paralympic Games 2022 in Bejing), several targeted research projects were initiated by WADA’s DBS steering committee early 2020. To support realization of the ambitious timeline, the following projects are being applied for as targeted research. The first subproject deals with the stability of DBS samples. Of particular interest is how the stability of the substances in the dried state appears on the paper of the card. Factors such as temperature, light, and humidity should also be considered. Several model compounds from various classes of prohibited substances will be included in this study.

Main Findings

The stability of prohibited substances on dried blood spots (DBS) is generally assumed as superior to the storage under liquid conditions. Nevertheless, stability is not warranted per se for all target analytes and all conditions. Under consideration of the reanalysis of samples that were fortified with model compounds (originally stored for 365 days at room temperature, 4 °C or -20°C with/without desiccant) from various classes (anabolics, peptide hormones, β2-agonists, metabolic modulators, diuretics, stimulants, narcotics, glucocorticoids and β –blockers) and subsequently stored for another two years at -20°C showed excellent stability. All model compounds included were still detectable. Additionally, the potential impact of an intercontinental flight was found to be negligible for the selected model drugs. Another newly performed stability study over five months (at room temperature, 4 °C or -20°C with/without desiccant) with new model compounds (incl. HIF-stabilizers etc.) showed that storing at room temperature without desiccant and exposure to light will cause considerable losses for some of the highly volatile compounds. Results for storing at 4°C and -20°C showed equivalent results to the formerly performed study. Thus, storage at 4° C (or -20°C) with desiccant in the dark is recommended for long-term storage of DBS doping control samples.