Homovanillic acid (HVA) measurement in urine is used for screening children for catecholamine-secreting tumors such as neuroblastoma, pheochromocytoma, and other neural crest tumors and monitoring those who have had treatment for these tumors. HVA measurement is also useful to diagnose children with disorders of catecholamine metabolism such as monoamine oxidase-A deficiency and dopamine beta-hydroxylase deficiency, which results in either decreased or elevated urinary HVA values, respectively. Treatment with L-dopa can impact test results and should be discontinued 24 hours prior to collection. Bactrim can impact test results and should be noted at time of collection.
Specimen Type
Urine
Container
24hr Ur 50% Acetic A
Collection Instructions
Container/Tube: 24 Hour urine collection with 25 mL of 50% acetic acid as a preservative Specimen: Entire 24 Hr container or a 5 mL aliquot of a well mixed 24 h collection Transport Temperature: Refrigerated Stability: 28 Days Refrigerated 180 Days Frozen Collection Instructions: 1. Collect a 24-hour urine specimen. 2. Add 25 mL of 50% acetic acid as preservative at start of collection. If specimen is refrigerated during collection, preservative may be added up to 12 hours after collection. Use 15 mL of 50% acetic acid for children less than 5 years old. This preservative is intended to achieve a pH of between approximately 1 and 5. If necessary, adjust urine pH to 1 to 5 with 50% acetic or hydrochloric acid.
Transport Instructions
Refrigerated
Specimen Stability
28 Days Refrigerated 180 Days Frozen
Methodology
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
