Download Catecholamines, Fractionated, 24-Hour Urine

Catecholamines, Fractionated,
24-Hour Urine
μg/24-h
1-7
<8
<11
2-24
Norepinephrine
3-8 y
9-12 y
13-17 y
Adults
5-41
5-50
12-88
15-100
Total N+E
3-8 y
9-12 y
13-17 y
Adults
9-51
9-71
13-90
26-121
Dopamine
3-8 y
9-12 y
13-17 y
Adults
80-378
51-474
51-645
52-480
Creatinine
3-8 y
9-12 y
13-17 y
Adults
g/24-h
0.11-0.68
0.17-1.41
0.29-1.87
0.63-2.50
Method
• High-performance liquid chromatography (HPLC), electrochemical
detection
• Analytical sensitivity: 2 μg/L for
epinephrine and norepinephrine;
10 μg/L for dopamine
• Creatinine concentration also
reported
Specimen Requirements
10 mL room temperature aliquot of a
24-h urine; 4.5 mL minimum
Collect urine with 25 mL of 6N HCl.
Record total volume on vial and
request form.
Interpretive Information
• Pheochromocytoma
• Neuroblastoma
• Paragangliomas
• Stress
It is preferable for the patient to be off
medications for 3 d prior to collection;
however, common antihypertensives
cause minimal or no interference.
Patient should avoid alcohol, coffee,
tea, tobacco, and strenuous exercise
prior to collection.
43
Alphabetical Test
Section
Clinical Background
Catecholamines are synthesized in
chromaffin cells of the sympathetic
nervous system: epinephrine by the
adrenal medulla, and norepinephrine
and dopamine by the adrenal medulla
and postganglionic sympathetic
neurons. Catecholamines are excreted
in urine both intact and as metabolites
(metanephrines and vanillylmandelic
acid).
Elevated urinary catecholamine
concentrations are detected in the
majority of patients with pheochromocytoma. In patients with paroxysmal
symptoms or hypertension, the
sensitivity of testing can be increased
by beginning urine collection immediately following an episode. The
pattern of catecholamine secretion
differs among tumor types:
pheochromocytomas generally
produce both norepinephrine and
epinephrine; paragangliomas secrete
norepinephrine; and neuroblastomas
produce excessive dopamine.
Clinical Use
• Diagnose catecholamine-secreting
tumors
Reference Range
Epinephrine
3-8 y
9-12 y
13-17 y
Adults
39627X