Vanillylmandelic Acid (VMA), 24-Hour Urine
Also known as: 3-Methoxy-4-Hydroxymandelic Acid, 24-Hour Urine, VMA, 24-Hour Urine
Use
Diagnose pheochromocytoma, VMA is of value for evaluation of hypertension, diagnose and follow up neuroblastoma, ganglioneuroma, and ganglioneuroblastoma. Most neuroblastoma patients excrete excess HVA in 24-hour collections. If VMA and HVA are both used in work-up, up to 80% of all cases will be detected.
Special Instructions
Record total 24-hour urine volume on the request form. Patient should avoid using salicylates, caffeine, phenothiazine, and antihypertension agents, as well as coffee, tea, chocolate, fruit (especially bananas), and vanilla-containing substances 72 hours prior to collection.
Limitations
This test was developed and its performance characteristics determined by LabCorp. It has not been cleared or approved by the Food and Drug Administration. Some neuroblastoma patients may not have elevated VMA despite having the condition. Up to 32% of patients with neuroblastoma do not show increased levels of VMA.
Methodology
Mass Spectrometry
Biomarkers
LOINC Codes
- 3122-9
- 9624-8
- 3122-9
Result Turnaround Time
3-4 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
4 mL aliquot
Minimum Volume
1 mL aliquot
Container
Plastic urine container, no preservative (preferred), or acidic preservative
Collection Instructions
Instruct the patient to void at 8 AM and discard the specimen. Then collect all urine, including the final specimen voided at the end of the 24-hour collection period (ie, 8 AM the next morning). Measure and record total urine volume. Mix well; send aliquot. Label container with patient's name, date and time collection started, and date and time collection completed.
Patient Preparation
Patient should avoid salicylates, caffeine, phenothiazine, and antihypertension agents. Also coffee, tea, chocolate, fruit (especially bananas and any vanilla containing substances for 72 hours prior to collection).
Storage Instructions
Vanillylmandelic acid is stable at room temperature unpreserved for seven days.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 7 days |
| Refrigerated | 14 days |
| Frozen | 14 days |