Sample Preparation for Storage Stability Evaluation

Briefly, an additional lot of K₂EDTA-treated whole blood was used to prepare samples to evaluate short-term storage stability at room temperature and −20°C conditions. Following the sample preparation protocols previously stated, samples were prepared in replicates of six for time points of 1 day, 7 days, and 28 days for each storage condition. Plasma separation card and dried blood spot samples were stored in air-tight bags with desiccant while wet plasma samples were pre-aliquoted into 1.5 mL polypropylene tubes. Day zero and blank card samples were extracted on the same day of preparation to provide baseline data. Method blank and bioreclamation plasma samples were also extracted at each time point to provide quality control. All stability test samples were extracted and prepared for analysis as described above.