Table 3.

Inter- and Intra assay precision of the Aβ peptides using both normalization methods of Pittsburgh assays

		V2.0 assay (%)
PAβ V2.0 assay		Intra-assay (n = 6)		Inter-assay (n = 5)
Aβ1–40	pg/mL	Aβ1–38 IS Normalized	Aβ1–40 IS Normalized	Aβ1–38 IS Normalized	Aβ1–40 IS Normalized
Level 1	37.5	6.5	5.5	3.4	1.8
Level 2	146.4	7.9	7.0	5.9	2.6
Level 3	382.5	5.9	4.6	2.3	1.7
Aβ1–42	pg/mL	Aβ1–38 IS Normalized	Aβ1–42 IS	Aβ1–38 IS Normalized	Aβ1–42 IS Normalized
Level 1	82.8	6.8	4.6	4.3	4.8
Level 2	49.5	5.6	4.9	5.8	4.2
Level 3	13.9	4.1	5.3	4.2	3.0
Aβ1–42/Aβ1–40		Aβ1–38 IS Normalized	Aβ1–40 IS and Aβ1–42 IS Normalized	Aβ1–38 IS Normalized	Aβ1–40 IS and Aβ1–42 IS Normalized
Level 1	2.208	2.2	2.3	3.2	3.9
Level 2	0.338	5.2	5.1	6.6	6.6
Level 3	0.036	4.5	4.4	5.9	4.9
		V1.0 assay (%)
PAβ V1.0 assay		Intra-assay (n = 6)		Inter-assay (n = 5)
Aβ1–40	pg/mL	Aβ1–38 IS Normalized	Aβ1–40 IS Normalized	Aβ1–38 IS Normalized	Aβ1–40 IS Normalized
Level 1	37.5	3.4	1.9	4.9	0.8
Level 2	146.4	3.7	3.4	4.7	2.7
Level 3	382.5	6.7	4.4	2.6	3.0
Aβ1–42	pg/mL	Aβ1–38 IS Normalized	Aβ1–42 IS Normalized	Aβ1–38 IS Normalized	Aβ1–42 IS Normalized
Level 1	82.8	3.2	2.2	4.3	0.7
Level 2	49.5	2.8	3.4	5.3	2.6
Level 3	13.9	7.3	5.9	5.5	4.8
Aβ1–42/Aβ1–40		Aβ1–38 IS Normalized	Aβ1–40 IS and Aβ1–42 IS Normalized	Aβ1–38 IS Normalized	Aβ1–40 IS and Aβ1–42 IS Normalized
Level 1	2.208	1.5	2.6	2.0	2.6
Level 2	0.338	2.3	2.0	2.4	3.2
Level 3	0.036	4.2	4.1	5.3	4.6