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Test ID VMA Vanillylmandelic Acid (VMA), 24 Hour, Urine

Useful For

Screening children for catecholamine-secreting tumors with a 24 hour 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)

Reporting Name

Vanillylmandelic Acid, 24 Hr, U

Specimen Type

Urine

Container/Tube: Plastic, 10-mL urine tube (T068)

Specimen Volume: 5 mL

Collection Instructions:

1. Collect a 24-hour urine specimen.

2. Add 25 mL of 50% acetic acid as preservative at the 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 <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 HCl acid.

Additional Information:

1. Patient's age and 24-hour volume are required.

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

3. See Urine Preservatives in Special Instructions for multiple collections.

Forms: If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

Neurology Test Request Form-General (T732) (http://www.mayomedicallaboratories.com/it-mmfiles/neurology-request-form.pdf)

Oncology Test Request Form (T729) (http://www.mayomedicallaboratories.com/it-mmfiles/oncology-request-form.pdf)

 

Urine Preservative Collection Options

Ambient

No

Refrigerated

No

Frozen

No

6N HCl

Yes

50% Acetic Acid

Preferred

Na2CO3

No

Toluene

No

6N HNO3

Yes

Boric Acid

Yes* (pH must be <5)

Thymol

No

*If boric acid is used, note on specimen container. Also, verify that pH is in desired range (pH=1-5). If pH is outside of desired range, adjust pH with a stronger acid (acetic acid is preferred but other acids listed above could be used if available) in a dropwise fashion to bring pH into desired range.

Specimen Minimum Volume

2 mL

Specimen Stability Information

Specimen Type Temperature Time
Urine Refrigerated (preferred) 7 days
  Frozen  7 days

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 1 of the above-mentioned tumors.

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): <8.0 mg/24 hours

Cautions

Administration of L-dopa may falsely-increase vanillylmandelic acid (VMA) results. Patients receiving L-dopa should stop taking it for 24 hours before and during the collection.

 

All patients receiving L-dopa should be identified to the laboratory when VMA and homovanillic acid (HVA) tests are ordered.

 

Values are more commonly elevated during a hypertensive episode.

 

Values may be normal in some individuals with pheochromocytoma.

 

Bactrim may interfere with detection of the analyte. All patients taking Bactrim should be identified to the laboratory when VMA and HVA tests are ordered.

 

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

Day(s) Performed

Monday through Friday; 8 a.m.

Report Available

2 days (not reported on Sunday)

Performing Laboratory

Mayo Medical Laboratories in Rochester

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

NY State Approved

Yes