Tube fill level assessment and timeline of sample processing. (A), Evaluation of the level of tube fullness based on draw order. **** P < 0.0001, 1-way ANOVA; (B), Fraction of blood collection tubes with high and low fill level; (C), Documented timeline for each sample following the whole ISO and CEN/TS workflows. Timeline represented in minutes; values above the violin plot are mean values with SD. Abbreviation: ns, not significant.