Fig 6. Effect of extreme storage temperatures on plasma separation and DNA yield in study cohort IV.
(A) Representative image of cfDNA BCTs centrifuged after 3 days of storage at RT, 4°C and 40°C. RT storage resulted in expected plasma separation with defined buffy coat layer and clear yellow plasma fraction. Extreme temperature conditions resulted in an expanded cellular interface layer or hemolytic plasma at 4°C or 40°C, respectively. (B) Effect of extreme temperatures on genomic DNA release (402 bp LINE-1 qPCR fragment). Statistically significant differences between K2EDTA and cfDNA BCT storage conditions determined by one-way ANOVA are marked with ** (p ≤ 0.01). Shown are box plots with 1.5 x IQR applied to create whiskers. (C) Obtained mean plasma volume with SD for indicated storage conditions.