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|80495:VANILLYLMANDELIC ACID (VMA), URINE|
|Alias Names:||VMA / 3-methoxy-4-hydroxy-manelic acid, VMA, Urine|
|Methodology:||High Performance Liquid Chromatography (HPLC)|
|Released:||24-72 hours after setup at PeaceHealth Laboratories’ reference lab.|
|Specimen Collection Details|
|Collection:||24-hour or random urine. Refrigerate during and after collection. NOTE: Patient to abstain from medications for 72 hours prior to collection.|
|Handling:||5 mL aliquot from a well-mixed 24-hour or random collection. Refrigeration is the preferred method of preservation. Record total volume and collection time interval on transport tube and requisition.|
|Stability:||7 days refrigerated or 14 days frozen. Specimen unstable ambient.|
|Standard Volume:||5 mL urine.|
|Minimum Volume:||1 mL urine.|
|Comments:||Moderately elevated VMA (vanillylmandelic acid) can be caused by a variety of factors such as essential hypertension, intense anxiety, intense physical exercise, and numerous drug interactions (including some over-the-counter medications and herbal products).
Medications that may interfere with catecholamines and their metabolites include amphetamines and amphetamine-like compounds, appetite suppressants, bromocriptine, buspirone, caffeine, chlorpromazine, clonidine, disulfiram, diuretics (in doses sufficient to deplete sodium), epinephrine, glucagon, guanethidine, histamine, hydrazine derivatives, imipramine, levodopa (L-dopa, Sinemet®), lithium, MAO inhibitors, melatonin, methyldopa (Aldomet®), morphine, nitroglycerin, nose drops, propafenone (Rythmol), radiographic agents, rauwolfia alkaloids (Reserpine), tricyclic antidepressants, and vasodilators. The effects of some drugs on catecholamine metabolite results may not be predictable.
|Vanillylmandelic acid (VMA) results are expressed as a ratio to creatinine excretion (mg/g cr). VMA mass per day (mg/d) is not reported on specimens from patients younger than 18 years of age, the urine collection is random or other than 24-hour, or the urine volume is less than 400 mL/24 hours.
The VMA-to-creatinine ratio wil be reported when the patient is under 18 years, the urine collection is random or other than 24-hours, or the urine volume is less than 400 mL/24 hours.
|VMA Urine||≥18 years||0.0-7.0 mg/d|