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Subject: Homovanillic Acid, Urine (HVA)
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HVA is the main terminal metabolite of catecholamine neurotransmitter, dopamine. For the diagnosis of neuroblastoma, it is important to carry out simultaneous determinations of HVA and VMA because either or both elevated.
Normal range: 0.0–15.0 mg/day.
Assist in the diagnosis of pheochromocytoma, neuroblastoma, and ganglioblastoma
Monitor the course of therapy
Screening for catecholamine-secreting tumors in children when accompanied by VMA
Evaluating patients with possible inborn errors of catecholamine metabolism
Schizotypal personality disorders
Preferred specimen is 24-hour urine, because of intermittent excretion.
Moderately elevated HVA may 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 include amphetamines and amphetamine-like compounds, appetite suppressants, bactrim, 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), and vasodilators. The effects of some drugs on catecholamine metabolite results may not be predictable.