Table 2.

Concentrations of internal QCs observed bias, within-run repeatability and total analytical repeatability.

QC concentration level	Metanephrine			Normetanephrine			3-methoxytyramine
	QC 1	QC 2	QC 3	QC 1	QC 2	QC 3	QC 1	QC 2	QC 3
QC concentration, nmol/L	0.27	0.60	2.7	0.29	0.64	2.9	0.40	0.75	1.4
Bias, mean % from target	−12	8.3	9.5	−6.2	6.8	10	−13	−0.3	8.9
Within-run repeatability, CV%	8.4	3.1	3.5	14	5.1	4.1	13	3.7	3.0
Total analytical repeatability, CV%	14	11	7.0	26	11	12	20	11	12