The design and evaluation of a shaped filter collection device to sample and store defined volume dried blood spots from finger pricks

Table 1 DNA concentration per μl of eluate determined in International Standard Units from Chelex and Qiagen extracted blood spots and whole blood

	Mean ISU per μl eluate	95% CI	Coefficient of variation	Minimum ISU per μl eluate	Maximum ISU per μl eluate	t -test result
Chromosomal target (18 s)
Chelex GB003	53.1	(49.4 to 56.7)	17.7%	33.5	72.5
Chelex 3MM	54.6	(52.1 to 57.1)	12.0%	40.8	65.2	0.461
Qiagen GB003	32.7	(28.8 to 36.6)	30.5%	11.5	49.6
Qiagen 3MM	12.0	(9.9 to 14.1)	45.2%	3.2	27.5	<0.001
200 μ Raw blood	853.6	(790.3 to 917.0)
Mitchondrial target
Chelex GB003	62.7	(56.5 to 68.9)	24.9%	41.5	105.5
Chelex 3MM	84.9	(80.2 to 89.6)	14.0%	58.3	103.2	<0.001
Qiagen GB003	63.3	(59.8 to 66.9)	13.3%	44.2	75.6
Qiagen 3MM	42.7	(38.6 to 46.8)	22.5%	23.7	60.5	<0.001
200 μl Raw blood	1718.8	(1640.8 to 1796.8)

Two separate real-time PCRs were used to assay chromosomal (18 s) and mitochondrial loci. The P values were generated by comparing the level of DNA eluted from 3MM and GB003 with Chelex or Qiagen DNA mini extractions using an unpaired t-test. Assumptions of equal variance were tested by ensuring there was less than a twofold difference between the standard deviations of the two groups compared.

ISSN: 1475-2875