Vanillylmandelic Acid (VMA), Urine
Also known as: VMA U
Use
The Vanillylmandelic Acid (VMA), Urine test is primarily used as an initial test for the diagnosis and monitoring of neuroblastoma. It should be ordered concurrently with Homovanillic Acid (HVA), Urine to improve diagnostic accuracy. This test helps in the assessment of catecholamine metabolism, where significant increases may indicate a secreting neuroendocrine tumor. The metabolites are measured as a ratio to creatinine excretion to account for variable urine concentrations.
Special Instructions
Patients should abstain from medications for 72 hours prior to collection to avoid interference with catecholamine metabolites. Collections should be refrigerated during the 24-hour period. Record total volume and collection time interval accurately on the transport tube and test request form.
Limitations
The test results may be influenced by medications, stress, diet, and physical activity, leading to false positives or alterations in catecholamine metabolite levels. Medications such as amphetamines, caffeine, and tricyclic antidepressants can interfere with results. No reference intervals are provided for results in mg/L, only as ratios to creatinine, which assists in evaluating abnormal values in context of urine concentration.
New York Approved
Methodology
Mass Spectrometry
Biomarkers
LOINC Codes
- 35674-1
- 2162-6
- 3122-9
- 50948-9
- 9624-8
- 30571-4
- 19153-6
- 30211-7
Result Turnaround Time
1-5 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
4 mL
Minimum Volume
1 mL
Container
ARUP standard transport tube
Collection Instructions
Transfer a 4 mL aliquot from a well-mixed 24-hour collection to an ARUP standard transport tube. Record total volume and collection time interval.
Patient Preparation
Abstain from medications for 72 hours prior to collection.
Storage Instructions
Refrigerated
Causes for Rejection
Specimen types other than urine.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | Unacceptable |
| Refrigerated | 1 week |
| Frozen | 2 weeks |