Catecholamines, Fractionated, Urinary Free, 24-Hour Urine

Also known as: Dopamine, 24-Hour Urine, Epinephrine, 24-Hour Urine, Fractionation, Urinary Free Catecholamines, Free Catecholamine Fractionation, Norepinephrine, 24-Hour Urine

Clinical Use

Order Test

Use

Work up neuroblastoma; diagnose pheochromocytoma. Pheochromocytomas and occasional paragangliomas may cause persistent or paroxysmal hypertension. Work up palpitation, severe headache, diaphoresis. Urine collections are preferred to blood sampling when there is suspicion for tumor (eg, family history of MEA II) when hypertension is not paroxysmal. Evaluate for possible multiple endocrine adenomatosis type II.

Special Instructions

Not provided.

Limitations

False-negatives and false-positives can occur. Urine collections for metanephrines are among the best tests for pheochromocytoma. Neuroblastoma is better evaluated with urinary collections for HVA and VMA. MHPG (3-methoxy-4-hydroxyphenylethylene glycol) is a major metabolite of norepinephrine in the central nervous system and is a metabolite of some neuroblastomas. The assay may not accurately detect pheochromocytomas unless the specimen is collected during a hypertensive episode.

Test Details

Methodology

Mass Spectrometry

Biomarkers

Dopamine

Analyte

Dopamine

Concentration / Level • Quantitative (Continuous) (e.g., copies/mL, % expression)

Epinephrine

Analyte

Epinephrine

Concentration / Level • Quantitative (Continuous) (e.g., copies/mL, % expression)

Norepinephrine

Analyte

Norepinephrine

Concentration / Level • Quantitative (Continuous) (e.g., copies/mL, % expression)

LOINC Codes

Order Codes

92938-0 - Catecholamines 3 Pnl Ur

Result Codes

11046-0 - Epineph Ur-mCnc
2232-7 - Epineph 24h Ur-mRate
2667-4 - Norepineph Ur-mCnc
2668-2 - Norepineph 24h Ur-mRate
2217-8 - DOPamine Ur-mCnc
2218-6 - DOPamine 24h Ur-mRate

Result Turnaround Time

4-7 days

Specimen

Urine

Volume

30 mL aliquot

Minimum Volume

4 mL aliquot (Note: This volume does not allow for repeat testing.)

Container

Brown urine container with 30 mL 6N HCl preservative. Caution: Strong acid. May cause skin burns.

Collection Instructions

Instruct the patient to void at 8 a.m. and discard the specimen. Preservative must be added to the container prior to the start of collection. Then collect all urine including the final specimen voided at the end of the 24-hour collection period (i.e., 8 a.m. the next morning). Label container. Keep collection on ice. Measure and record the total urine volume on the test request form. Remove 20 mL aliquot. pH should be <5.

Patient Preparation

Avoid patient stress. Many drugs (reserpine and α-methyldopa, levodopa, monoamine oxidase inhibitors, and sympathomimetic amines) may interfere and should be discontinued two weeks prior to specimen collection. Nose drops, sinus and cough medicines, bronchodilators and appetite suppressants, α2-agonists, calcium channel blockers, converting enzyme inhibitors, bromocriptine, phenothiazine, tricyclic antidepressants, α- and β-blockers, and labetalol may interfere. Mandelamine® interferes, but thiazides do not. Caffeine products should be avoided before and during collection. The patient should not be subjected to hypoglycemia or exertion. Increased intracranial pressure and clonidine withdrawal can cause false-positive results.