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Test ID: VH    
Vanillylmandelic Acid (VMA) and Homovanillic Acid (HVA), Pediatric, 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

Elevated values of homovanillic acid (HVA), vanillylmandelic acid (VMA), and other catecholamine metabolites (eg, dopamine) may be suggestive of the presence of a catecholamine-secreting tumor (eg, neuroblastoma, pheochromocytoma, or other neural crest tumors). HVA and VMA levels may also be useful in monitoring patients who have been treated as a result of the above-mentioned tumors. HVA levels may also be altered in disorders of catecholamine metabolism: monamine oxidase-A deficiency can cause decreased urinary HVA values, while a deficiency of dopamine beta-hydrolase (the enzyme that converts dopamine to norepinephrine) can cause elevated urinary HVA values.

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.

VMA

<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): not applicable

 

HVA

<1 year: <35 mg/g creatinine

1 year: <23 mg/g creatinine

2-4 years: <13.5 mg/g creatinine

5-9 years: <9 mg/g creatinine

10-14 years: <12 mg/g creatinine

> or =15 years (adults): not applicable

Interpretation Provides information to assist in interpretation of the test results

Screening children for catecholamine-secreting tumors*

*Positive test could be due to a genetic or non-genetic condition. Additional confirmatory testing is required.

 

Supporting a diagnosis of neuroblastoma

 

Monitoring patients with a treated neuroblastoma

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 homovanillic acid (HVA)/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 HVA tests are ordered.

 

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 / Metanephrines, Fractionated, Free, Plasma

-METAF / Metanephrines, Fractionated, 24 Hour, Urine

-CATU / Catecholamine Fractionation, Free, 24 Hour, 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 Disease. Edited by N Blau, M Duran, M E Blaskovics.London UK, Chapman and Hall Medical, 1996, pp 79-98

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

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