Table 3.

GuHCl addition during sample preparation impacts amyloid-β peptide recovery from Alzheimer’s disease cerebrospinal fluid aliquots

	Aβ1–42		Aβ1–40		Aβ1–38		Aβ1–37		Aβ1–34
	GuHCl before transfer	GuHCl after transfer	GuHCl before transfer	GuHCl after transfer	GuHCl before transfer	GuHCl after transfer	GuHCl before transfer	GuHCl after transfer	GuHCl before transfer	GuHCl after transfer
No. of subjects	7	7	7	7	7	7	7	7	5	3
Difference between 0.1-ml and 0.5-ml aliquots (%)	5	90	9	63	9	46	9	48	10	14
SD (%)	8	35	8	26	7	23	7	27	10	10
Range (%)	− 6 to 18	48–146	− 5 to 16	27–112	1–23	30–89	0–22	24–95	− 2 to 25	5–25
p Value (0.1 ml vs. 0.5 ml)	0.1103	0.001	0.043	0.002	0.0104	0.0047	0.0428	0.0074	0.1199	0.1368

Abbreviations: Aβ Amyloid-β, AD Alzheimer’s disease, GuHCl Guanidine hydrochloride

p values were calculated by paired t test. Boldface values indicate noteworthy changes concomitant with a p value < 0.05

Difference between 0.1-ml and 0.5-ml aliquots (%) = ([b − a]/[a]) × 100, where:

a = [Aβ_1-X] recovered from 0.1-ml aliquots

b = [Aβ_1–X] recovered from 0.5-ml aliquots