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Test Code VMAR Vanillylmandelic Acid, Random, Urine

Reporting Name

Vanillylmandelic Acid, Random, U

Useful For

Screening children for catecholamine-secreting tumors with a random urine collection when requesting vanillylmandelic acid only

 

Supporting a diagnosis of neuroblastoma

 

Monitoring patients with a treated neuroblastoma

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Urine


Advisory Information


In the past, this test has been used to screen for pheochromocytoma. However, VMA is not the analyte of choice to rule out a diagnosis of pheochromocytoma. Recommended tests for this purpose are:

-PMET / Metanephrines, Fractionated, Free, Plasma

-METAF / Metanephrines, Fractionated, 24 Hour, Urine

-CATU / Catecholamine Fractionation, Free, 24 Hour, Urine



Necessary Information


1. Patient's age is required.

2. All patients receiving L-dopa should be identified to the laboratory when this test is ordered.

3. Bactrim may interfere with detection of the analyte. All patients taking Bactrim should be identified to the laboratory when this test is ordered.



Specimen Required


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.

Supplies: Urine Tubes, 10 mL (T068)

Collection Container/Tube: Clean, plastic urine collection container

Submission Container/Tube: Plastic, 10-mL urine tube

Specimen Volume: 5 mL

Collection Instructions:

1. Collect a random urine specimen.

2. Adjust the random urine pH to a level between 1 and 5 by adding 50% acetic acid dropwise and checking the pH.


Specimen Minimum Volume

2 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Refrigerated (preferred) 28 days
  Frozen  180 days

Reference Values

<1 year: <25.0 mg/g creatinine

1 year: <22.5 mg/g creatinine

2-4 years: <16.0 mg/g creatinine

5-9 years: <12.0 mg/g creatinine

10-14 years: <8.0 mg/g creatinine

≥15 years (adults): <7.0 mg/g creatinine

Day(s) and Time(s) Performed

Monday, Thursday; 8 a.m.

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

84585

LOINC Code Information

Test ID Test Order Name Order LOINC Value
VMAR Vanillylmandelic Acid, Random, U 3124-5

 

Result ID Test Result Name Result LOINC Value
60274 Vanillylmandelic Acid, Random, U 3124-5

Clinical Reference

1. Hyland K: Disorders of neurotransmitter metabolism. In: Blau N, Duran M, Blaskovics ME, Gibson KM, eds. Physician’s Guide to the Laboratory Diagnosis of Metabolic Diseases. Springer; 2003:107-122. Doi: 10.1007/978-3-642-55878-8_8

2. Gitlow SE, Bertrani LM, Rausen A, Gribetz D, Dziedzic SW: Diagnosis of neuroblastoma by qualitative and quantitative determination of catecholamine metabolites in urine. Cancer. 1970 Jun;25(6):1377-1383

3. Strenger V, Kerbl R, Dornbusch HJ, et al: Diagnostic and prognostic impact of urinary catecholamines in neuroblastoma patients. Pediatr Blood Cancer. 2007 May;48(5):504-509

4. Barco S, Gennai I, Reggiardo G, et al: Urinary homovanillic and vanillylmandelic acid in the diagnosis of neuroblastoma: report from the Italian Cooperative Group for Neuroblastoma. Clin Biochem. 2014 Jun;47(9):848-852

5. Matthay KK, Maris JM, Schleiermacher G, et al: Neuroblastoma. Nat Rev Dis Primers. 2016 Nov 10;2:16078. doi: 10.1038/nrdp.2016.78

Method Description

Vanillylmandelic acid (VMA) is measured by solid-phase extraction (SPE) of a 1-mL aliquot of urine. A known amount of stable-isotope labeled VMA internal standard (IS) is added to each urine specimen prior to SPE. VMA and IS are eluted from the SPE column with methanol. The methanol is evaporated and the VMA and IS are redissolved in liquid chromatography tandem-mass spectrometry (LC-MS/MS) mobile phase. A portion of this prepared extract is injected onto a LC column that separates VMA and IS from the bulk of any remaining specimen matrix. The VMA and IS are measured by mass spectrometry/tandem-mass spectrometry using the selected reaction monitoring mode. VMA is quantified using the ratio to IS versus urine calibrators.(Magera MJ, Thompson AL, Stoor AL, et al: Determination of vanillylmandelic acid in urine by stable isotope dilution and electrospray tandem mass spectrometry. Clin Chem 2003;49:825-826; Eisenhofer G, Grebe S, Cheung NV: Monoamine-producing tumors. In Rifai N, Horvath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018:chap 63)

Analytic Time

2 days (not reported on Sundays)

Reject Due To

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Method Name

Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)