Catecholamines, Blood and Urine
Epinephrine, norepinephrine, dopamine.
To assist in diagnosing catecholamine-secreting tumors, such as those found in the adrenal medulla, and in the investigation of hypertension. The test is used to assist in diagnosing pheochromocytoma (a benign tumor of the adrenal gland) and paraganglioma; also as a work-up of neuroblastoma (a rare tumor that most often originates in the nervous tissue of the adrenal medulla).
Instruct the patient to follow a normal-sodium diet for 3 days before testing, to avoid consumption of foods high in amines for 48 hr before testing, and to withhold food and fluids for 10 to 12 hr before the test. Instruct the patient to avoid self-prescribed medications for 2 wk before testing (especially appetite suppressants and cold and allergy medications, such as nose drops, cough suppressants, and bronchodilators). Instruct the patient to withhold prescribed medication (especially methyldopa, epinephrine, levodopa, and methenamine mandelate) by medical direction. Protocols may vary among facilities. The patient should also abstain from smoking tobacco for 24 hr before testing. Usually, a 24-hr urine collection is ordered. Instruct the patient to avoid excessive exercise and stress during the 24-hr collection of urine. As appropriate, provide the required urine collection container and specimen collection instructions.
Method: High-performance liquid chromatography.
|Blood||Conventional Units||SI Units|
|Epinephrine (supine)||(Conventional Units × 5.46)|
|Child||Less than 450 pg/mL||Less than 2,457 pmol/L|
|Adult||Less than 200 pg/mL||Less than 1,092 pmol/L|
|Norepinephrine (supine)||(Conventional Units × 5.91)|
|Child||Less than 1,200 pg/mL||Less than 7,100 pmol/L|
|Adult||Less than 410 pg/mL||Less than 2,420 pmol/L|
|Dopamine (supine or upright)||(Conventional Units × 6.53)|
|Child–adult||Less than 20 pg/mL||Less than 130 pmol/L|
|Generally, higher values are expected in specimens collected when the patient has been standing; dopamine values are unaffected by position.|
|Urine||Conventional Units||SI Units|
|Epinephrine||(Conventional Units × 5.46)|
|Child||Less than 11 mcg/24 hr||Less than 60 nmol/24 hr|
|Adult||Less than 20 mcg/24 hr||Less than 100 nmol/24 hr|
|Norepinephrine||(Conventional Units × 5.91)|
|Child||Less than 50 mcg/24 hr||Less than 300 nmol/24 hr|
|Adult||Less than 120 mcg/24 hr||Less than 709 nmol/24 hr|
|Dopamine||(Conventional Units × 6.53)|
|Child||Less than 414 mcg/24 hr||Less than 2,703 nmol/24 hr|
|Adult||Less than 485 mcg/24 hr||Less than 3,167 nmol/24 hr|
|Due to the numerous factors that can elevate catecholamines, urine specimens are thought to provide more reliable results in the pediatric population.|
Critical Findings and Potential Interventions
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