Quantitative Measurement of Plasma Free Metanephrines by a Simple and Cost-Effective Microextraction Packed Sorbent with Porous Graphitic Carbon and Liquid Chromatography-Tandem Mass Spectrometry

Table 3

Comparison of biochemical tests for screening for PPGL using clinical specimens.

Clinical specimen metabolite	Plasma metanephrines (pg/mL)			Urinary free catecholamines (μg/day)				Urinary free metanephrines (μg/day)			Urinary VMA (mg/day)
	MN	NMN	MN + NMNM	EPI	NE	DA	All	MN	NMN	MN + NMN
TP, n	13	19	19	7	13	3	15	10	18	19	15
TN, n	73	83	73	82	82	81	79	82	83	82	78
FP, n	10	0	10	1	1	2	4	1	0	1	5
FN, n	8	2	2	14	8	18	6	11	3	2	6
Sensitivity (%)	61.9	90.5	90.5	33.3	61.9	14.3	71.4	47.6	85.7	90.5	71.4
Specificity (%)	88.0	100	88.0	98.8	98.8	97.6	95.2	98.8	100	98.8	94.0

TP: true positive; TN: true negative; FP: false positive; FN: false negative; EPI: epinephrine; NE: norepinephrine; DA: dopamine.