VMA Quantitative, Urine (Sendout)

Useful For:

• Screening children for catecholamine-secreting tumors with a urine collection when requesting testing for only vanillylmandelic acid
• Supporting a diagnosis of neuroblastoma
• Monitoring patients with a treated neuroblastoma

Test Highlights:

Vanillylmandelic acid (VMA) and other catecholamine metabolites such as Homovanillic Acid, Urine (Sendout) [RUHVAG] measurement in urine are used for screening children for catecholamine-secreting tumors such as neuroblastoma and other neural crest tumors and monitoring those who have had treatment for these tumors.

More than 90% of individuals with neuroblastoma have elevated VMA and/or HVA.

VMA is not the analyte of choice for diagnosis of pheochromocytoma, which is better detected by testing for metanephrines.

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.

Patient Preparation: Administration of L-dopa may falsely-increase vanillylmandelic acid results; it should be discontinued 24 hours prior to and during collection of specimen.

Interpretation:

Vanillylmandelic acid and/or homovanillic acid concentrations are elevated in most patients (more than 90%) with neuroblastoma; both tests should be performed. A positive test could be due to a genetic or nongenetic condition. Additional confirmatory testing is required.

A normal result does not exclude the presence of a catecholamine-secreting tumor.

Elevated values are suggestive of a pheochromocytoma, but they are not diagnostic.

Cautions:

Values are more commonly elevated during a hypertensive episode.

Values may be normal in some individuals with pheochromocytoma.

All patients taking Bactrim should be identified to the laboratory when VMA and HVA tests are ordered due to potential interference.

24-Hour Urine:

• Add 25 mL of 50% acetic acid as preservative to an amber polyethylene 24-hr urine collection container at the start of collection.
  • For children <5 years old, use 15 mL of 50% acetic acid.
• If specimen is refrigerated during collection, preservative may be added up to 12 hours after collection.
• Refer to Mayo Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens for additional information on acceptable collection conditions.
• Collect urine for 24 hours.
• Refrigerate urine within 4 hours of completion of collection.

Mayo Preservative Supply: 50% Acetic Acid, 25 mL [T008]

Random Urine: Collect random urine in a clean, plastic urine collection container.

Outside Laboratories:

• 24-Hour: Mix specimen well and measure urine volume. Record the collection interval and total volume on the DLMP requisition.
• Aliquot 2-5 mL urine into a separate screw-cap aliquot.
• Check the pH. If necessary, adjust the pH to a level between 1 and 5 by adding 50% acetic acid dropwise.
• Refrigerate urine while awaiting shipment. Transport with a cold pack.

Stability: Refrigerated (preferred): 28 days; Frozen: 180 days; Ambient: Unacceptable.

SPS:

• 24-Hour: Mix specimen well and measure the urine volume. Record the total volume and collection interval on the requisition.
• Aliquot 2-5 mL urine into a separate screw-cap urine aliquot.
• Refrigerate urine.

Result-at-Entry:

• UVMAQI (VMA Interval): <Enter the collection interval in hours>
• UVMQTV (VMA Total Volume): <Enter the total volume in mL>

Sendouts:

• Check the pH. If necessary, adjust the pH to a level between 1 and 5 by adding 50% acetic acid dropwise (hydrochloric acid can be used instead for adjusting 24-hr specimens).
• Order the Mayo Test corresponding to the specimen type received.
  
  • 24-Hour: VMA. Collection interval and total volume are required.
  • Random: VMAR.
• Interfaced: Yes [Interface: 601; Worksheet: MARF]
  • For random specimens, queue the order across the interface, then change the test code to VMAR (and remove code VMA) in MayoAccess.

Stability: Refrigerated (preferred): 28 days; Frozen: 180 days; Ambient: Unacceptable.