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Test ID: VMA    
Vanillylmandelic Acid (VMA), 24 Hour, 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): <8.0 mg/24 hours

Interpretation Provides information to assist in interpretation of the test results

Vanillylmandelic acid and/or homovanillic acid concentrations are elevated in most patients (more than 90%) 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 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 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;48:504-509

Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test