Vanillylmandelic Acid (VMA) and Homovanillic Acid (HVA), Urine
Also known as: VH
Use
This test is primarily used for the initial diagnosis and monitoring of neuroblastoma by measuring the levels of vanillylmandelic acid (VMA) and homovanillic acid (HVA) in urine. These metabolites are markers of catecholamine metabolism, and their elevated levels can be indicative of neuroendocrine tumors such as neuroblastoma. Accurate measurement of these metabolites assists in monitoring disease progression and response to treatment. Multiple factors such as medications, stress, and diet can affect the levels of VMA and HVA, hence careful preparation and collection are essential for reliable results.
Special Instructions
Patients need to abstain from medications for 72 hours before collection to ensure accurate results. The test involves a 24-hour urine collection, which must be refrigerated during the collection period to maintain sample integrity. Proper documentation, including total volume and collection times, is essential for result interpretation. The specimen must follow specific shipping and storage protocols to maintain stability.
Limitations
This laboratory-developed test has not been cleared or approved by the US FDA and is performed in a CLIA-certified laboratory for clinical purposes. It cannot provide a complete picture of catecholamine metabolism on its own. Individual variations such as stress, physical exertion, and certain medications can cause elevations in VMA and HVA levels, which might not indicate a pathological condition. Interfering substances include a wide variety of over-the-counter medications, supplements, or herbal products, which may lead to false positive or negative results.
New York Approved
Methodology
Mass Spectrometry
Biomarkers
LOINC Codes
- 35674-1
- 2162-6
- 2436-4
- 48767-8
- 3122-9
- 59587-6
- 9624-8
- 30571-4
- 13760-4
- 19153-6
- 30211-7
Result Turnaround Time
1-5 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
4 mL
Minimum Volume
1 mL
Container
ARUP standard transport tube
Collection Instructions
Collect 24-hour urine. Refrigerate during collection period. Transfer a 4 mL aliquot from a well-mixed collection to the transport tube.
Patient Preparation
Abstain from medications for 72 hours prior to collection.
Storage Instructions
Refrigerated transport. Stability: Refrigerated for 1 week; Frozen for 2 weeks.
Causes for Rejection
Specimen types other than urine.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | Unacceptable |
| Refrigerated | 1 week |
| Frozen | 2 weeks |