Vanillylmandelic Acid (VMA), 24-Hour Urine

Also known as: 3-Methoxy-4-Hydroxymandelic Acid, 24-Hour Urine, VMA, 24-Hour Urine

Clinical Use

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

Not provided.

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.

Test Details

Methodology

Mass Spectrometry

Biomarkers

Vanillylmandelic Acid

Analyte

VMA, Urine A

Concentration / Level • Quantitative (Continuous) (e.g., copies/mL, % expression)

VMA, Urine, 24hr

Concentration / Level • Quantitative (Continuous) (e.g., copies/mL, % expression)

LOINC Codes

Order Codes

3122-9 - VMA 24h Ur-mRate

Result Codes

9624-8 - VMA Ur-mCnc
3122-9 - VMA 24h Ur-mRate

Result Turnaround Time

3-4 days

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).