Lab Information Manual

Laboratory:

Clinical Biochemistry (SPECIAL CHEMISTRY)

Test Name:

VANILLYLMANDELIC ACID (VMA), RANDOM OR 24H URINE - (U)

Test Code: VMA

Clinical Information:

Description: Homovanillic acid (HVA) and vanillylmandelic acid (VMA) are the preferred tests for screening for neuroblastoma in a random urine specimen.

Supporting neuroblastoma diagnosis & monitoring patients with a treated neuroblastoma.

HVA and VMA tests are performed and reported as a panel.

Test Indications: HVA and VMA levels are elevated in more than 90% of patients with neuroblastoma. 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 HVA and VMA values are suggestive of a pheochromocytoma, but they are not diagnostic. For investigation of PHEOCHROMOCYTOMA in adults, the test FRACTIONATED METANEPHRINES - (U) should be ordered only.

Patient preparation instructions: See More Information below on interfering medication, consult your physician prior to discontinuing.

Numerous over-the-counter and herbal products/supplements may affect VMA levels and should be discontinued for 72 hours prior to collection.

Collection Devices:

Preferred Device:	1 - Urine Collection Container - 24 h Urine Collection Container - 24 h Manufacturer: VWR Scientific Products/Simport Plastics Catalogue #: CA73960-110
Alternate Device:	1 - Urine Collection Container, Random 100 mL Urine Collection Container, Random 100 mL Manufacturer: Starplex Scientific Inc. (Etobicoke, ON) Catalogue #: 3008-1 - (Fresh)

Specimen Required:

Urine: 10.0 mL

Pediatric Urine: 1.0 mL

Collection Information: If collecting 24h urine, refrigerate during collection.

If collecting random urine, morning void is preferred.

For details refer to
JA110-50-01B Random Urine Processing Flow Chart
JA110-50-01A 24 Hour Urine Processing Flow Chart
Specimen Stability:
Ambient: 48 hours
Refrigerated: 4 weeks
Frozen: 6 months

Referral:

Urine: 10.0 mL

Pediatric Urine: 1.0 mL

Shipping & Storage: Store and ship frozen.
Testing Laboratory (MB):

HSC Clinical Biochemistry

Mass Spectrometry/Metabolic Lab

(204)-787-4530

Requisition:

_SH Urine Testing Requisition (R250-10-95)

Reference Values:

AGE	VMA
<1 year	≤ 14.3 µmol/mmol creatinine
1 year	≤ 12.9
2–4 years	≤ 9.1
5-9 years	≤ 6.9
10-14 years	≤ 4.6
≤15 years	≤ 4.0

Slight or moderate increases in catecholamine metabolites may be due to extreme anxiety, essential hypertension, intense physical exercise, or drug interactions. Significant increase of one or more catecholamine metabolites (several times the upper reference limit) is associated with an increased probability of a secreting neuroendocrine tumor.
Method of Analysis: Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

Availability:

Within 10 Days

For urgent testing, consult Clinical Biochemist of Duty 431-276-4861

More Information:

Interpretation & Assay Interferences: Medications that may interfere with catecholamines and their metabolites include amphetamines and amphetamine-like compounds, appetite suppressants, bromocriptine, buspirone, caffeine, chlorpromazine, clonidine, disulfiram, diuretics (in doses sufficient to deplete sodium), epinephrine, glucagon, guanethidine, histamine, hydrazine derivatives, imipramine, levodopa (L-dopa, Sinemet), lithium, MAO inhibitors, melatonin, methyldopa (Aldomet), morphine, nitroglycerin, nose drops, propafenone (Rythmol), radiographic agents, rauwolfia alkaloids (Reserpine), tricyclic antidepressants, and vasodilators. The effects of some drugs on catecholamine metabolite results may not be predicable.