Table 1. Sample information.

Comparative experiment	Sample group	Blood volume (ml)	Participated volunteers (n)	Mean age at sampling (age range)	Sample number (n)
					Peripheral blood	Hemolytic	Gradient
(a)	#1	5	20	64.3 (34–82) years	0	20	20
	#2	2	20	64.6 (30–86) years	0	20	20
	#3	0.1	20	69.7 (46–91) years	0	20	20
(b)	#4	5	10	61.7 (51–70) years	0	10	10
	#5	2	10	67.8 (57–76) years	0	10	10
	#6	0.1	10	67.3 (55–86) years	0	10	10
(c)	#7	5	3	52.0 (28–66) years	6*	3	3
	#8	2	3	72.0 (69–76) years	3	3	0
	#9	0.1	3	67.7 (65–69) years	3	3	0

^*(3 blood samples from sample group #7) × (each technical replicate) = 6 microarray samples.