VMA (Vanillylmandelic Acid), Random Urine

LAB750

Patient Preparation: It is preferable for the patient to be off medications for three days prior to collection. However, common antihypertensives (diuretics, ace inhibitors, calcium channel blockers, alpha and beta blockers) cause minimal or no interference. Patient should avoid alcohol, coffee, tea, tobacco (including use of nicotine patch), bananas, citrus fruits and strenuous exercise prior to collection.

Specimen Type: Urine

Collection Container/Type: Sterile container

Submission Container/Tube: Sterile container

Specimen Volume: 10 mL

Collection Instructions: 

1. Collect specimen with 6N HCL.
2. pH adjusted to <3.0 using 6N HCl Urine without preservative is acceptable if pH is below 6 and the sample is shipped frozen.

5 mL

Room temperature: 10 days

Refrigerated: 14 days

Frozen: 1 year

pH >3.0 and received frozen

3-6 days

Urinary vanillylmandelic acid (VMA) concentration is useful in the biochemical diagnosis and monitoring of neuroblastomas [1]. VMA measurement from random urine specimens, expressed as the ratio of VMA to creatinine, may provide equivalent diagnostic value as VMA measurement from 24-hour urine specimens for the evaluation of neuroblastomas [1].

Neuroblastomas occur predominantly in children and are the most common malignancy under 1 year old. Neuroblastomas are catecholamine-metabolizing tumors with limited ability to store and secrete catecholamines. Thus, catecholamine metabolites-including VMA and homovanillic acid (HVA)-are more reliable than catecholamines as biochemical markers for neuroblastomas [1]. VMA and HVA levels, usually measured simultaneously, can be elevated in neuroblastomas as well as other catecholamine-secreting tumors, such as pheochromocytoma [1]. In patients with familial dysautonomia (Riley-Day syndrome), a neurological disorder found mainly in individuals of Ashkenazi Jewish descent, VMA levels are generally elevated while HVA levels may be normal or decreased [2].

Urinary VMA and HVA levels may have limited accuracy for diagnosis of neuroblastomas with high-risk metastatic biology [1]. Because poor prognosis is associated with immaturity of catecholamine metabolism, dopamine levels in urine or blood have been proposed as an additional marker to aid in diagnosis and monitoring of neuroblastomas [3].

The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.

References
1. Eisenhofer G. Monoamine-producing tumors. In: Rifai R, et al. eds. Tietz Textbook of Laboratory Medicine. 7th ed. Elsevier Inc; 2022.
2. Axelrod FB. Familial dysautonomia. Muscle Nerve. 2004;29(3):352-363.
3. Brodeur GM, et al. J Clin Oncol. 1993;11(8):1466-1477.