Table 2. Comparison of HTT MSD assay performance in two independent laboratories.

Performance measures derived from the dataset shown in Fig 5.

Parameter	2B7/4C9-biotin		2B7/MW1-biotin
	NL (CRL-LEI)	US (CRL-SHR)	NL (CRL-LEI)	US (CRL-SHR)
LOD	~6 pM	1.5 pM	0.1 pM	0.2 pM
Dynamic range	~3.5 logs (6 to >4000 pM)	2–4000 pM	~3.5 logs (0.1–4000 pM)	0.5–4000 pM
Precision	0.3–7% CV	4–20% CV	0.3–10%CV	3–12% CV
Range of HTT concentrations in Q175 WT brains (fmol/mg protein)	37–46	1.1–2.5	<LLOQ	LLOQ-2.7
Range of HTT concentrations in Q175 HET brains (fmol/mg protein)	139–306	41–129	644–1415	572–1899

LOD, limit of detection; LLoQ, lower limit of quantification.