Urine Metanephrines

General Information

A phaeochromocytoma is a rare (0.1-1.0 % of hypertensive population), catecholamine-secreting tumor derived from chromaffin cells. When such tumors arise outside of the adrenal gland, they are termed extra-adrenal phaeochromocytomas, or paragangliomas. Because of excessive catecholamine secretion, phaeochromocytomas may precipitate life-threatening hypertension or cardiac arrhythmias. If the diagnosis of a phaeochromocytoma is overlooked, the consequences can be disastrous, even fatal; however, if a pheochromocytoma is found, it is potentially curable. Phaeochromocytomas are often associated with other endocrine tumours.

Symptoms of phaeochromocytoma are due to catecholamine excess and include:

Sustained or paroxysomal hypertension
Weight loss
Sweating
Headache
Palpitations
Anxiety

Since the secretion of the catecholamines, and hence the symptoms, from a phaeochromocytoma may be paroxysmal (i.e. short and frequent) it is recommended that 3 successive 24 hour urine collections are performed to 'catch' the catecholamine secretion and hence ensure the correct diagnosis.

The metabolites of the catecholamines - normetadrenaline and metadrenaline (collectively known as metadrenalines) - can also be used for the diagnosis of phaeochromocytoma, with their meaurement in both urine and plasma recommended for diagnosis at the First International Symposium on Phaeochromocytoma in 2005 due to their increased diagnostic specificity when compared to catecholamines.

Measurement of urinary catecholamines will also be performed on all samples.

Patient Preparation

Analyses are performed on 24 hour urine collections. Under exceptional circumstances block-timed urines and random specimens may be analysed. The 24 hour urines must be collected into acid (e.g. 50 mL of 3 mol/L hydrochloric acid); acidification of specimens following receipt by the laboratory is unacceptable.

Substances which can interfere both in vivo and in vitroinclude:

Tricyclic antidepressants
Phenoxybenzamine
Calcium channel blockers
Stimulants (e.g. caffeine, nicotine)
Levodopa
Paracetamol

Patietns should avoid caffeine for 24 hours and during collection of your specimen. In addition, the following drugs should be avoided for one week prior to the collection, if clinically feasible:

Phenothiazines (used to treat mental or emotional disorders)
Tricyclic antidepressants including imipramine, as well as labetalol, sotalol and monoamine oxidate inhibitors (MAOIs)
Chlorpromazine (used to treat psychosis)

Notes

For interpretation contact duty biochemist (bleep 2506)

Reference Range

Table 1. 24hr Urine Metadrenaline Ranges

Analyte	Age	Collection	µmol/ 24 hr	Source
Normetadrenaline	Adult	24 hr	<4.9	Locally derived
	0-2 months	24 hr	<0.85	Tietz
	3-5 months	24 hr	<0.61
	6-8 months	24 hr	<0.6
	9-11 months	24 hr	<0.56
	1yr	24 hr	<0.65
	2-5 yr	24 hr	<0.6
	6-9 yr	24 hr	<0.96
	10-15 yr	24 hr	<1.59
Metadrenaline	Adult	24 hr	<2.0	Tietz
	0-2 months	24 hr	<0.19
	3-8 months	24 hr	<0.21
	9-11 months	24 hr	<0.51
	1 yr	24 hr	<0.26
	2-5 yr	24 hr	<0.5
	6-9 yr	24 hr	<0.7
	10-15 yr	24 hr	<1.23
3 MT	Adult	24 hrs	<2.75	Measurement of urinary metanephrines to screen for pheochromocytoma in an unselected hospital referral population. Shine Bet al. Clin Chem 2006 Nov;52(11):2060-4. Epub 2006 Sep 21
	0- 4 years	24 hrs	<0.62	Paediatric Reference Values for Urinary Catecholamine Metabolites Evaluated by High Performance Liquid Chromatography and Electrochemical Detection1
	5-15 years	24 hrs	<1.26

Table 2. Random Urine Metadrenaline Ranges

Analyte	Age	Collection	umol/mmol creatinine	Source
Normetadrenaline	Adult	Random	<0.35	Locally derived
	0-2 months	Random	<1.32	Chromsystems Dialog Magazine, 2009, http://chromsystems.com/en-gb/news/dialog
	3-5 months	Random	<0.91
	6-11 months	Random	<0.57
	1yr	Random	<0.35
	2-4 yr	Random	<0.24
	5-9 yr	Random	<0.16
	10-15 yr	Random	<0.11
Metadrenaline	Adult	Random	<0.11	Locally derived
	0-5 months	Random	<0.21	Chromsystems Dialog Magazine, 2009, http://chromsystems.com/en-gb/news/dialog
	6-11 months	Random	<0.13
	1 yr	Random	<0.12
	2-4 yr	Random	<0.11
	5-9 yr	Random	<0.10
	10-15 yr	Random	<0.07
3MT	Adult	Random	<0.15	Locally derived
	<1yr	Random	<1.5	Annales de Biologie Clinique. Volume 60, Numéro 1, 15-36, Janvier - Février 2002
	1 yr	Random	<0.75
	2-15 yr	Random	<0.36

Source of Reference Range

Clinical Guide to Laboratory Tests, 3rd Edition, Teitz, 1995 ISBN 0-7216-5035-X and local validation

Specifications

EQA Scheme?: Yes
EQA Status: NEQAS

Department

Preferred Sample Type

Sample Processing in Laboratory

Sample Preparation

Turnaround Time

Sample Stability

Urine Metanephrines

General Information

Patient Preparation

Notes

Reference Range

Source of Reference Range

Specifications

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