Comparison of ELISA- and SIMOA-based quantification of plasma Aβ ratios for early detection of cerebral amyloidosis

Table 2 Characteristics of the study population and subgroups in total and stratified by amyloid-PET status

	Study population			CN subgroup			aMCI subgroup
	Total	Aβ−	Aβ+	Total	Aβ−	Aβ+	Total	Aβ−	Aβ+
Number (%)	199	161 (81)	38 (19)	161	137 (85)	24 (15)	38	24 (63)	14 (37)
Mean age (SD), years	70 (6)	69 (6)	72 (5)^b	69 (6)	69 (6)	71 (5)	71 (7)	69 (6)	74 (6)
Female, n (%)	89 (45)	72 (45)	17 (45)	73 (45)	61 (45)	12 (50)	16 (42)	11 (46)	5 (36)
Mean education (SD), years	14 (3)	14 (3)	14 (4)	14 (3)	14 (3)	14 (4)	14 (4)	14 (4)	14 (3)
*APOE-ε4* carriers/homozygous, *n (*%)	92/7 (46)	70/5 (43)	22/2 (58)	82/6 (51)	65/5 (47)	17/1 (71)^a	10/1 (26)	5/0 (21)	5/1 (36)
Median MMSE (IQR), /30	29 (2)	29 (2)	29 (2)^a	29 (2)	29 (2)	29 (2)	29 (2)	29 (1)	27 (3)^a
Median ELISA plasma Aβ_1–42/Aβ_1–40 (IQR)	0.17 (0.03)	0.18 (0.03)	0.15 (0.02)^d	0.18 (0.03)	0.18 (0.03)	0.15 (0.02)^d	0.17 (0.02)	0.18 (0.03)	0.16 (0.01)^b
Median ELISA plasma Aβ_1–42/t-tau (IQR)	1.23 (0.50)	1.32 (0.49)	1.00 (0.29)^d	1.25 (0.49)	1.29 (0.49)	1.02 (0.34)^c	1.21 (0.58)	1.41 (0.51)	0.89 (0.27)^d
Median SIMOA plasma Aβ_1–42/Aβ_1–40 (IQR)	0.26 (0.06)	0.26 (0.06)	0.21 (0.05)^d	0.26 (0.06)	0.26 (0.05)	0.21 (0.05)^d	0.24 (0.07)	0.28 (0.06)	0.22 (0.03)^c
Median SIMOA plasma Aβ_1–42/t-tau (IQR)	0.93 (0.41)	0.99 (0.39)	0.73 (0.24)^d	0.94 (0.37)	0.99 (0.38)	0.74 (0.27)^c	0.92 (0.45)	1.14 (0.33)	0.70 (0.21)^d

aMCI amnestic mild cognitive impairment, Aβ β-amyloid, CDR Clinical Dementia Rating, CN cognitively normal, ELISA enzyme-linked immunosorbent assay, IQR interquartile range, MMSE Mini-Mental State Examination, SIMOA single molecule array, t-tau total tau. p values reflect comparisons between Aβ−ve and Aβ+ve groups: ^ap < 0.05; ^bp < 0.01; ^cp < 0.001; ^dp < 0.0001

ISSN: 1758-9193