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Test ID: VMAR    
Vanillylmandelic Acid (VMA), Random, Urine

Useful For Suggests clinical disorders or settings where the test may be helpful

Screening children for catecholamine-secreting tumors

 

Supporting a diagnosis of neuroblastoma

 

Monitoring patients with a treated neuroblastoma

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Vanillylmandelic acid (VMA) and other catecholamine metabolites (homovanillic acid [HVA] and dopamine) are typically elevated in patients with catecholamine-secreting tumors (eg, neuroblastoma, pheochromocytoma, and other neural crest tumors). VMA and HVA levels may also be useful in monitoring patients who have been treated as a result of 1 of the above-mentioned tumors.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

<1 year: <27.0 mg/g creatinine

1 year: <18.0 mg/g creatinine

2-4 years: <13.0 mg/g creatinine

5-9 years: <8.5 mg/g creatinine

10-14 years: <7.0 mg/g creatinine

> or =15 years (adults): < or =6.0 mg/g creatinine

Interpretation Provides information to assist in interpretation of the test results

Vanillylmandelic acid (VMA) and/or homovanillic acid (HVA) concentrations are elevated in more than 90% of patients with neuroblastoma; both tests should be performed. A positive test could be due to a genetic or nongenetic condition.  Additional confirmatory testing is required.

 

A normal result does not exclude the presence of a catecholamine-secreting tumor.

 

Elevated VMA values are suggestive of a pheochromocytoma, but they are not diagnostic.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Administration of L-dopa may falsely increase vanillylmandelic acid (VMA) results. Patients receiving L-dopa should stop taking it for 24 hours before and during the collection.

 

All patients receiving L-dopa should be identified to the laboratory when VMA and homovanillic acid tests are ordered.

 

Values are more commonly elevated during a hypertensive episode. 

 

Values may be normal in some individuals with a pheochromocytoma.

 

In the past, this test has been used to screen for pheochromocytoma. However, VMA is not the analyte of choice to rule out a diagnosis of pheochromocytoma. Recommended tests for this purpose are:

-PMET/81609 Metanephrines, Fractionated, Free, Plasma

-METAF/83006 Metanephrines, Fractionated, 24 Hour, Urine

-CATU/9276 Catecholamine Fractionation, Free, Urine

Clinical Reference Provides recommendations for further in-depth reading of a clinical nature

1. Hyland K, Biaggioni I, Elpeleg ON, et al: Disorders of neurotransmitter metabolism. In Physician's Guide to the Laboratory Diagnosis of Metabolic Diseases. Edited by N Blau, M Duran, ME Blaskovics. London, UK, Chapman and Hall Medical, 1996, pp 79-98

2. Gitlow SE, Bertrani LM, Rausen A, et al: Diagnosis of neuroblastoma by qualitative and quantitative determination of catecholamine metabolites in urine. Cancer 1970;25(6):1377-1383

3. Pacak K, Linehan M, Elsenhofer G, et al: Recent advances in genetics, diagnosis, localization, and treatment of pheochromocytoma. Ann Internl Med 2001;134(4):315-329

4. Strenger V, Kerbl R, Dornbusch HJ, et al: Diagnostic and prognostic impact of urinary catecholamines in neuroblastoma patients. Pediatr Blood Cancer. 2007;48(5):504-509