This test is used to screen for rare tumours and other abnormalities in the production of catecholamines, particularly in children.
Catecholamines (epinephrine, norepinephrine, and dopamine) are organic compounds involved in neurotransmission. They are produced in the nerve cells and adrenal glands. Homovanillic acid is one of the inactive derivatives of catecholamines excreted by the adrenal medulla and certain tumours (pheochromocytomas, neuroblastomas). For screening purposes, HVA testing is simpler for the patient as it involves a simple urine specimen. See also the following headings: Catecholamines, Metanephrines and VMA.
HVA (and VMA) levels are high in more than 90 % of neuroblastoma cases. High levels can also be due to hereditary or non-hereditary conditions. All positive results should be confirmed with catecholamine measurements. A negative result does not completely rule out the possibility of a neuroblastoma.