CATECHOLAMINES FRACTIONATED URINARY FREE 24 HOUR URINE

General Information

HLAB/HOL Code: CATU
UPHSM LIS Test #: 026060
Schedule:
Testing Time: 4-7 Days
Testing Lab: Labcorp

Specimen Info
Only 1 specimen type required, unless otherwise specified

Volume: 30.0mL
Temperature: Refrigerated
Tube Type: Urine - 24 hr urine
Collection Info:
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: 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.

Collection:
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.


Patient Preparation:
Avoid patient stress. Many drugs (reserpine and alpha 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.

Causes for Rejection:
Specimen with no preservative; original container with pH >5


Specimen Acceptability

Cause for Rejection:
Specimen with no preservatives; original container with pH >5

Methods

Liquid chromatography/tandem mass spectrometry (LC/MS-MS)

Clinical Utilities

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.

Limitations:
False-negatives and false-positives occur. Urine collections for metanephrines are among the best tests for pheochromocytoma.  Sheps et al use urinary catecholamine fractionation as confirmation, following a metanephrine test.  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.

CPT Codes

82384

* The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding
is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.

Reference Range

Adults:

Epinephrine:
• 0-9 years: 0-11 μg/24 hours
• 10-19 years: 0-18 μg/24 hours
• >19 years: 0-20 μg/24 hours

Norepinephrine:
• 0-9 years: 0-59 μg/24 hours
• 10-19 years: 0-90 μg/24 hours
• >19 years: 0-135 μg/24 hours

Dopamine:
• 0-9 years: 0-414 μg/24 hours
• 10-19 years: 0-575 μg/24 hours
• >19 years: 0-510 μg/24 hours