Blood samples (4.5 ml) were collected in lavender top EDTA
(ethylenediaminetetraacetic acid) BD Vacutainer tubes (Becton
Dickinson, Franklin Lakes, NJ, USA) with informed written consent
from 25 healthy volunteers for all methods except the PAXgene.
Samples for the PAXgene system were collected in 8.5-ml tubes
provided by the manufacturer. QIAamp and PAXgene samples were
extracted according to the manufacturers’ instructions. Fermentas
blood samples (200 ll) were extracted using a modified protocol.
Briefly, chloroform was added to the blood sample, and the sample
was vortexed to homogeneity. All centrifugations were performed
at 16,000g. After the precipitation solution was added (according to
manufacturer’s protocol), the centrifugation lasted for 10 min. Finally,
a DNA pellet was resuspended in 100 ll (10 mM Tris–HCl
[pH 7.5] and 0.1 mM EDTA).