Reference Ranges

Clinical Neurochemistry Laboratory
Reference Ranges

Reference Ranges for Plasma Catechols and Metanephrines

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TABLE OF CONTENTS

PART I: CATECHOLS

Reference Ranges — General

Menkes Reference Range Ratios

PART II: METANEPHRINES

Reference Ranges (Not adjusted for Gender or Age)

Reference Ranges (Adjusted for Gender or Age)

Statistics

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REFERENCE RANGES FOR PLASMA CATECHOLS AND METANEPHRINES

PART I: REFERENCE RANGES FOR PLASMA CATECHOLS

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Reference range	Lower limit	Upper limit	Units
NE	80	498	pg/ml
EPI	4	83	pg/ml
DHPG	518	1408	pg/ml
DOPA	922	2483	pg/ml
DA	3	46	pg/ml
DOPAC	675	2636	pg/ml

Menkes Reference Range Ratios

Plasma values	DOPA:DHPG ratio	DOPAC:DHPG ratio
Patients with Menkes disease	6.2-34.2	4.4-19.7
Pediatric control subjects	1.7-3.3	1.5-3.2

Notes about Reference Ranges: Reference ranges above are for antecubital venous plasma levels of catechols, in patients with an indwelling intravenous catheter who have been supine for at least 20 minutes before the sample was drawn.

PART II: REFERENCE RANGES FOR PLASMA METANEPHRINES

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Reference Ranges (Not Adjusted for Gender or Age)

Reference ranges determined from data in 178 normotensive and hypertensive individuals, including 100 men and 78 women, ages ranging from 18 to 72 yrs. Data was log-transformed before analysis and upper and lower reference limits (URLs; LRL's) determined from the 95% confidence limits (i.e., 2 standrad deviations above and below the geometric mean).

Analyte		Geometric Mean	Uper Reference Limit	Lower Reference Limit
Normetanephrine (NMN)
	(pg/mL)	45	112	18
	(pmol/mL)	0.25	0.61	0.10
Metanephrine (MN)
	(pg/mL)	27	61	12
	(pmol/mL)	0.14	0.31	0.06
Total Normetanephrine (tNMN)
	(pg/mL)	1390	3170	610
	(pmol/mL)	7.60	17.32	3.33
Total Metanephrine (tMN)
	(pg/mL)	735	1706	316
	(pmol/mL)	3.73	8.66	1.60

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Reference Ranges (Adjusted for Gender or Age)

Reference ranges below are adjusted for a highly significant influence (P<0.001) of gender on plasma concentrations of metanephrine and total metanephrine and a highly significant influence of age on plasma normetanephrine and total normetanephrine.

Analyte		Geometric Mean	Uper Reference Limit	Lower Reference Limit
Normetanephrine (NMN)
	age < 38 yr (pg/mL)	40	95	17
	age >= 38 yr (pg/mL)	51	125	21
Metanephrine (MN)
	Male (pg/mL)	29	62	21
	Female (pmol/mL)	24	55	11
Total Normetanephrine (tNMN)
	age < 38 yr (pg/mL)	1230	2806	540
	age = 38 yr (pg/mL)	1578	3266	762
Total Metanephrine (tMN)
	Male (pg/mL)	796	1734	540
	Female (pmol/mL)	662	1603	274

* Note: Appropriate determination of reference ranges requires samples taken from healthy volunteers with strict attention to the guidelines for blood sampling outlined in this procedure manual. Use of reference ranges from samples taken from hypertensives or hospital patients (although appropriate for diagnosis of pheochromocytoma in hospital patients or patients with documented hypertension) are likely to lead to elevated upper reference limits, totally inappropriate for screening for pheochromocytoma in patients with MEN2 or VHL disease. Data that is not normally distributed may be log-transformed to obtain a normal distribution before determination of reference limits (see below).

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Statistics. Estimation of Reference Ranges using log transformed data

Estimated Reference Ranges using X7 log NMN

Estimated Reference ranges using X8 log MN

Estimated reference ranges using X5 log NMNt

Estimated reference ranges using x1 log MNt