Catecholamine Fractionation, Free, 24 Hour, Urine
Use
An auxiliary test to fractionated plasma and urine metanephrine measurements in the diagnosis of pheochromocytoma and paraganglioma. It also serves as an auxiliary test to urine vanillylmandelic acid and homovanillic acid determination in the diagnosis and follow-up of patients with neuroblastoma and related tumors. This test is not useful as a first-line test for pheochromocytoma.
Special Instructions
Ordering guidance indicates greatest value when specimen is collected during a hypertensive episode. The 24‑hour volume (in milliliters) must be provided. Patient preparation: discontinue drugs that release or hinder metabolism of catecholamines (e.g., epinephrine, norepinephrine, dopamine) at least 1 week prior; stop any injections or infusions of these catecholamines at least 12 hours prior unless for drug monitoring. PDF forms include 24‑Hour Urine Preservatives‑Collection and Transportation guidelines and specific ordering forms for Oncology (T729) or Renal Diagnostics (T830).
Limitations
This test is not useful as a first‑line test for pheochromocytoma. Many physiologic and pathologic factors and medications (e.g., stress, posture, caffeine, nicotine, monoamine oxidase inhibitors, catecholamine reuptake inhibitors like cocaine or local anesthetics) can significantly impact catecholamine levels. Collection intervals shorter than 22 hours or longer than 26 hours may lead to rejection; environmental stressors and dietary factors may alter results.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
LOINC Codes
- 92938-0
- 13362-9
- 3167-4
- 2668-2
- 2232-7
- 2218-6
Result Turnaround Time
2-5 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
2 mL aliquot; requires 24‑hour total urine volume
Minimum Volume
2 mL
Container
Plastic vial (Sarstedt Aliquot Tube, 5 mL)
Collection Instructions
Add 25 mL of 50% acetic acid (15 mL for children <5 years) at start of 24‑hour collection to achieve pH ~2–4; collect urine for 24 hours; record total volume.
Patient Preparation
Discontinue catecholamine‑affecting drugs for at least 1 week; stop catecholamine injections/infusions for 12 hours prior unless monitoring.
Causes for Rejection
Collections 26 hours; improper preservatives or pH; random (non‑24‑hour) specimens.
Stability Requirements
| Temperature | Period |
|---|---|
| Refrigerated | 28 days |
| Frozen | 28 days |