Vanillylmandelic Acid and Homovanillic Acid, Random, Urine
Use
Homovanillic acid (HVA) and vanillylmandelic acid (VMA) measurements in urine are used for screening children for catecholamine-secreting tumors such as neuroblastoma, pheochromocytoma, and other neural crest tumors; they are also useful for monitoring patients after treatment for these tumors. Additionally, elevated or decreased HVA may indicate disorders of catecholamine metabolism such as monoamine oxidase‑A deficiency or dopamine beta‑hydroxylase deficiency. VMA is not ideal for pheochromocytoma diagnosis, for which metanephrines are preferred. Elevated concentrations of HVA and VMA are suggestive but not diagnostic; further confirmatory testing is required, and a normal result does not exclude disease.
Special Instructions
Not provided.
Limitations
VMA is not the analyte of choice for diagnosing pheochromocytoma. A normal result does not exclude presence of a catecholamine-secreting tumor. Elevated values are suggestive but not diagnostic. Medications like L‑dopa and Bactrim may falsely increase results and must be identified.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
LOINC Codes
- 90250-2 - VMA + HMA panel Ur
- 3124-5 - VMA/Creat Ur
- 11146-8 - HVA/Creat Ur
Result Turnaround Time
2-4 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
5 mL
Minimum Volume
2 mL
Container
Plastic, 10‑mL urine tube; clean, plastic urine collection container
Collection Instructions
Collect a random urine specimen. Adjust urine pH to between 1 and 5 by adding 50% acetic acid or hydrochloric acid dropwise.
Patient Preparation
Do not take L‑dopa for 24 hours prior to collection; identify patients on Bactrim.
Causes for Rejection
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.
Stability Requirements
| Temperature | Period |
|---|---|
| Refrigerated | 28 days |
| Frozen | 180 days |