VMA Quantitative, Urine (Sendout)

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General Information

Lab Name
VMA Quant, Urine
Lab Code
RUVMAQ
Epic Ordering
Vanillylmandelic Acid Quant, Urine (Sendout)
External Test Id
VMA, VMAR
Description

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

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.

References
Synonyms
3-Methoxy-4-Hydroxymandelic Acid, 4-Hydroxy-3-Methoxymandelic Acid, Neuroblastoma, Vanillylmandelic Acid (VMA) Urine, VMA, VMAR
Components

Interpretation

Method

Liquid Chromatography-Tandem Mass Spectrometry

Reference Range
See individual components
Ref. Range Notes

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.

Interferences and Limitations

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.

References

Ordering & Collection

Specimen Type
Urine
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.

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.

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

Handling Instructions

Outside Laboratories:

  • 24-Hour: Mix specimen well. Measure and record total volume. Note 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.

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

Quantity
requested: 5 mL urine
minimum: 2 mL urine

Processing

Processing
  • 24-Hour: Mix specimen well. Measure and record total volume. Note the collection interval and total volume on the requisition.
  • Aliquot 2-5 mL urine into a separate screw-cap vial.
  • Refrigerate urine.

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. 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.

Performance

LIS Dept Code
Sendouts Mayo Lab (RF) (MARF)
Performing Location(s)
Sendout Mayo Clinic Laboratories
800-533-1710

200 First Street Southwest
Rochester, MN 55901
Frequency
Performed: Monday - Friday. Report Available: 3-5 days.
Available STAT?
No

Billing & Coding

CPT codes
84585
LOINC
3122-9
Interfaced Order Code
UOW2054