Vanillylmandelic Acid (VMA)
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Vanillylmandelic acid (VMA), a metabolic by-product of norepinephrine and epinephrine, can be used to detect neuroblastoma and other tumors of neural crest origin.
The reference ranges of vanillylmandelic acid in children are as follows: [1, 2, 3]
Younger than 1 year: < 27 mg/g creatinine
Age 1-2 years: < 18 mg/g creatinine
Age 2-4 years: < 13 mg/g creatinine
Age 5-9 years: < 8.5 mg/g creatinine
Age 10-14 years: < 7 mg/g creatinine
The reference range in persons aged 15 years and older is 2-7 mg/24 hours.
Conditions associated with elevations in urinary vanillylmandelic acid (VMA) include the following:
Other neural crest tumors (eg, ganglioblastoma, ganglioneuroma)
Severe anxiety/stress
Specifics for collection and panels depend on the specimen type.
24-hour urine is collected as follows:
Container: Plastic 10-mL urine tube
Collection method: 24-hour urine collection
Specimen volume: 5 mL
Other instructions: (1) Add 25 mL of 50% acetic acid to collection vessel as a preservative and (2) note patient age and total urine volume
Random urine (only for children < 15 years) is collected as follows:
Container: Plastic 10-mL urine tube
Collection method: Random urine specimen
Specimen volume: 5 mL
Other instructions: (1) Adjust urine pH to 1 to 5 with 50% acetic or hydrochloric (HCl) acid, (2) note patient age, and (3) urine creatinine measurement required
Related tests: Urine creatinine, urine catecholamines, plasma free metanephrines, urine metanephrines, urine homovanillic acid (HVA)
Elevated metabolic by-products of catecholamines—dihydroxyphenylalanine (DOPA), dopamine, norepinephrine, and epinephrine—can be detected in the urine of patients with neuroblastoma and other tumors of neural crest origin. DOPA and dopamine are metabolized into their final product, homovanillic acid (HVA), while norepinephrine and epinephrine are metabolized into vanillylmandelic acid (VMA).
The biochemical pathway is as follows:
DOPA
Dopamine
Norepinephrine → Normetanephrine → VMA and 3-methoxyphenylethyleneglcol (MHPG)
Epinephrine → Metanephrine → VMA and 3-methoxyphenylethyleneglcol (MHPG)
Ninety percent of neuroblastoma tumors secrete these by-products. Children with dedifferentiated tumors tend to excrete higher levels of HVA than vanillylmandelic acid because these tumors have lost the final enzymatic pathway that converts HVA to vanillylmandelic acid. A low ratio of vanillylmandelic acid to HVA is consistent with a poorly differentiated tumor and indicates a poor prognosis.
In the evaluation of pheochromocytoma, vanillylmandelic acid is now considered the least-specific test for catecholamine metabolites, with a false-positive rate greater than 15%. Measurement of metanephrine, an intermediate metabolite between epinephrine and vanillylmandelic acid, is now considered the most sensitive and specific test for pheochromocytoma. Besides plasma free metanephrines and urine metanephrines, urine or plasma catecholamine tests are also preferred over vanillylmandelic acid testing.
Indications for testing of urine vanillylmandelic acid include the following:
Diagnostic workup of neuroblastoma
Follow-up monitoring in patients treated for neuroblastoma
Foods that can increase urinary catecholamines include the following:
Coffee
Tea
Bananas
Chocolate
Cocoa
Citrus fruits
Vanilla
Drugs that can increase urinary vanillylmandelic acid include the following:
Appetite suppressants
Caffeine
Histamine
Imipramine
Insulin
Epinephrine
Levodopa
Lithium
Morphine
Nitroglycerin
Rauwolfia alkaloids
Isoproterenol
Methocarbamol
Sulfonamide
Chlorpromazine
Drugs that can decrease urine vanillylmandelic acid include the following:
Clonidine
Disulfiram
Guanethidine
MAO inhibitors
Salicylates
Reserpine
Methyldopa
Burris CA, Ashwood ER, Burns DE. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 4th ed. St. Louis: Elsevier Saunders; 2006.
McPherson RA, Pincus MR. Henry’s Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia: Elsevier Saunders; 2011.
Wallach J. Interpretation of Diagnostic Tests. 9th ed. New York: Little, Brown; 2011.
Test ID: VH Vanillylmandelic Acid (VMA), Pediatric, Urine. Mayo Medical Laboratories. Available at http://www.mayomedicallaboratories.com/test-catalog/Clinical+and+Interpretive/9254. Accessed: 1/6/2014.
Hanna Lee Florida State University College of Medicine
Disclosure: Nothing to disclose.
Daniel J Van Durme, MD, FAAFP Professor and Chair, Department of Family Medicine and Rural Health, Director, Center of Global Health, Acting Director of Rural Health, Florida State University College of Medicine; Family Physician, Madison County Health Department
Daniel J Van Durme, MD, FAAFP is a member of the following medical societies: American Academy of Family Physicians, American Medical Association, American Public Health Association, Florida Medical Association, Society of Teachers of Family Medicine, Wilderness Medical Society, Physicians for Human Rights, National Rural Health Association, Association for Prevention Teaching and Research, Florida Academy of Family Physicians, World Organization of Family Doctors
Disclosure: Nothing to disclose.
Eric B Staros, MD Associate Professor of Pathology, St Louis University School of Medicine; Director of Clinical Laboratories, Director of Cytopathology, Department of Pathology, St Louis University Hospital
Eric B Staros, MD is a member of the following medical societies: American Medical Association, American Society for Clinical Pathology, College of American Pathologists, Association for Molecular Pathology
Disclosure: Nothing to disclose.
Vanillylmandelic Acid (VMA)
Research & References of Vanillylmandelic Acid (VMA) |A&C Accounting And Tax Services
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