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Catecholamines, Fractionated, Urinary Free, 24-Hour Urine
- Dopamine, 24-Hour Urine
- Epinephrine, 24-Hour Urine
- Fractionation, Urinary Free Catecholamines
- Free Catecholamine Fractionation
- Norepinephrine, 24-Hour Urine
Urinary epinephrine; urinary norepinephrine; urinary dopamine
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.
False-negatives and false-positives occur. Urine collections for metanephrines are among the best tests for pheochromocytoma.1 Sheps et al use urinary catecholamine fractionation as confirmation, following a metanephrine test.1 Neuroblastoma is better worked up with urinary collections for HVA and VMA. MHPG (3-methoxy-4-hydroxyphenylethylene glycol) is a major metabolite of norepinephrine in the central nervous system; it is a metabolite of some neuroblastomas.3
Liquid chromatography/tandem mass spectrometry (LC/MS-MS)
− 0 to 9 years: 0−11 μg/24 hours
− 10 to 19 years: 0−18 μg/24 hours
− >19 years: 0−20 μg/24 hours
− 0 to 9 years: 0−59 μg/24 hours
− 10 to 19 years: 0−90 μg/24 hours
− >19 years: 0−135 μg/24 hours
− 0 to 9 years: 0−414 μg/24 hours
− 10 to 19 years: 0−575 μg/24 hours
− >19 years: 0−510 μg/24 hours
The expression “free” in free catecholamine fractionation means unconjugated. This assay is of most value for pheochromocytoma when specimen is collected during a hypertensive episode. Since a 24-hour urine collection represents a longer sampling time than a random, or symptom-directed serum sample, and because catecholamine secretion by pheochromocytomas is intermittent, the urine test may detect some cases missed by a blood level.
30 mL aliquot
4 mL aliquot
Brown urine container with 30 mL 6N HCl preservative. Caution: Strong acid. May cause skin burns.
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.1 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.1,2
Instruct the patient to void at 8 AM 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 (ie, 8 AM the next morning). Label container. Keep collection on ice. Measure and record total urine volume on the test request form. Remove 20 mL aliquot. pH should be <5.
Refer to the Preservative Quick Reference Chart in Specimen Collection: Urine Specimens.
Refrigerate during and after collection.
30 days at 70°C
Causes for Rejection
Specimen with no preservative; original container with pH >5
Include 24-hour total urine volume on the test request form and date and time collection started and finished. Note: If original container is received with pH >3, but <5, adjust pH to <3 with 6N HCl.
|Order Code||Order Code Name||Order Loinc||Result Code||Result Code Name||UofM||Result LOINC|
|004176||Catecholamines,Ur.,Free,24 Hr||004193||Epinephrine, Urine||ug/L||11046-0|
|004176||Catecholamines,Ur.,Free,24 Hr||004194||Epinephrine, U, 24hr||ug/24 hr||2232-7|
|004176||Catecholamines,Ur.,Free,24 Hr||004201||Norepinephrine, Ur||ug/L||2667-4|
|004176||Catecholamines,Ur.,Free,24 Hr||004202||Norepinephrine,U,24h||ug/24 hr||2668-2|
|004176||Catecholamines,Ur.,Free,24 Hr||004203||Dopamine, Urine||ug/L||2217-8|
|004176||Catecholamines,Ur.,Free,24 Hr||004204||Dopamine, Ur, 24hr||ug/24 hr||2218-6|