ApoA-I, ADAMTS13 activity, and total active VWF levels in normal, sepsis, and TTP participants. (A) Boxplot of ApoA-I levels measured by ELISA in normal (n = 10), sepsis (n = 12), and TTP (n = 5) participants. P values for the comparisons of means, normal vs sepsis, and normal vs TTP from Dunnett’s test are both <.001. (B) Boxplot of ADAMTS13 activity levels in normal, sepsis, and presumptively diagnosed TTP participants. P values for the comparisons of means for normal vs sepsis and normal vs TTP from Dunnett’s test are .005 and <.001, respectively. (C) Distribution of ApoA-I and total active VWF levels in normal (green), sepsis (red), and TTP (black) participants. Total active VWF was determined by multiplying VWF antigen by VWF activation factor (binding to nanobody AU/VWFa-11). PNP, pooled normal plasma.