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HelpTest Code VMAR Vanillylmandelic Acid, Random, Urine
Reporting Name
Vanillylmandelic Acid, Random, UUseful For
Screening children for catecholamine-secreting tumors using a random urine collection when requesting vanillylmandelic acid only
Supporting a diagnosis of neuroblastoma
Monitoring patients with a treated neuroblastoma
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
UrineOrdering Guidance
In the past, this test has been used to screen for pheochromocytoma. However, vanillylmandelic acid (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 specimen collection.
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 or hydrochloric 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 |
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.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) Performed
Monday through Friday
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 Information
Vanillylmandelic acid (VMA) and other catecholamine metabolites (homovanillic acid [HVA] and dopamine) are typically elevated in patients with catecholamine-secreting tumors (eg, neuroblastoma, pheochromocytoma, and other neural crest tumors). VMA and HVA levels may also be useful in monitoring patients who have been treated as a result of one of the above-mentioned tumors.
Interpretation
Vanillylmandelic acid (VMA) and/or homovanillic acid concentrations are elevated in more than 90% of patients 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 VMA 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 a pheochromocytoma.
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 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 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)
Report Available
3 to 5 daysTest Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.Disease States
- Neuroblastoma