Cholesterol efflux capacity in control and Pcsk9 KO serum. Cholesterol efflux capacity (%) was calculated as F-cholesterol efflux (%) = F-cholesterol in medium / (F-cholesterol in medium + F-cholesterol in cells) × 100. Cholesterol efflux was induced by 5 μl serum incubation in triplicate (n = 5 per genotype) in THP-1 for 1 hour (A) and J774A.1 macrophage foam cells for 48 hours (B). Data represent the mean ± SEM. *P < 0.05.