Table 1. Analytical performance characteristics of the active VWF ELISA assay.

Parameter	Assay performance
Precision	Intra-assay (Mean [SD;%CV])	Inter-assay (Mean [SD;%CV])
	L 102% [7.3%; 7.2%]	L 107% [10.1%; 9.4%]
	M 182% [6.6%; 3.7%]	M 172% [7.6%; 4.4%]
	H 235% [5.7%; 2.4%]	H 226% [9.2%; 4.1%]
Accuracy	Spiked 1.0 μg/mL
	[E]OD 0.233 - [O]OD 0.230	[E]% 333 - [O]% 329—Rec% 99
	Spiked 0.75 μg/mL
	[E]OD 0.171 - [O]OD 0.175	[E]% 250 - [O]% 245—Rec% 98
	Spiked 0.5 μg/mL
	[E]OD 0.117 - [O]OD 0.122	[E]% 167 - [O]% 175—Rec% 105
	Spiked 0.35 μg/mL
	[E]OD 0.093 - [O]OD 0.101	[E]% 140 - [O]% 144—Rec% 103
	Spiked 0.25 μg/mL
	[E]OD 0.069 - [O]OD 0.076	[E]% 100 - [O]% 108—Rec% 108
Linearity	Spiked with R1306W aVWF
	Assessed: OD 0.073–0.635	(90.1%– 787.2% of NPP)
	Linear range: OD 0.073–0.342	(90.1%– 424.5% of NPP)
	Linearity curve through points:	R2 = 0.9923
	Dilution of L with H pool
	Range: OD 0.083–0.199
	Mix content—aVWF mean (SD)	- % of expected
	100% H / 0% L—236 (5.5)	- n.a.
	75% H / 25% L—208 (2.1)	- 103
	50% H / 50% L—165 (1.9)	- 97
	25% H / 75% L—147 (1.9)	- 108
	0% H / 100% L—103 (2.3)	- n.a.
	Linear fit [O]OD vs [E]OD:	R2 = 0.9879
	OD—% of NPP
LoQ	0.081–101.2
LoB	0.060–80.0
LoD	0.067–89.1
Stability	Baseline aVWF: 153% (SD 2.7%)
	Repeated freeze-thawing	Recovery extended storage
	Thaw #—mean (SD)—% Rel. to BL	t—mean (SD)—% Rel. to BL
	1–150 (3.8) - 98	24h -153 (2.6) - 100
	2–146 (3.2) - 95	48h - 152 (3.3) - 100
	3–138 (4.4) - 90	7d- 150 (4.0) - 98
	4–129 (3.2) - 84	1m - 146 (3.2) - 95
		2m - 147 (2.3) - 96

SD, standard deviation; CV, coefficient of varation; L, low; M, medium; H, high; E, expected; O, observed; OD, optical density; [E]_%/[O]_%, expected and observed active VWF (aVWF) level, as a % of NPP; LoQ, limit of quantitation; LoB, limit of blank; LoD, limit of detection; NPP, normal pooled plasma; Rel. to BL, relative to baseline value, calculated as 100x(observed value/baseline), expressed as %; t, timepoint; h, hours; d, days; m, month.