Catecholamines, Fractionated, Urinary Free and Vanillylmandelic Acid (VMA), 24-Hour Urine
Also known as: Vanillylmandelic Acid (VMA) and Catecholamines, Fractionated, Urinary Free, VMA and Catecholamines
Use
Collection is of greatest value for evaluation of hypertension if performed during a hypertensive episode. Test is used to evaluate hypertension, especially if paroxysmal and to evaluate orthostatic hypertension. Test is also useful in the diagnosis of pheochromocytoma and in the diagnosis and follow-up of neuroblastoma and ganglioneuroblastoma, retinoblastomas, carcinoid tumors, carotid body tumors, and stress. Preoperative evaluation of neoplasia of childhood, especially when the tumor is in or about the adrenals. Evaluate multiple endocrine adenomatosis. Evaluate patient with medullary carcinoma of thyroid (for coexistent pheochromocytoma).
Special Instructions
It is essential to include the 24-hour total urine volume on the test request form and specify the date and time that the urine collection was started and completed. If the original container is received with a pH greater than 3 but less than 5, it is necessary to adjust the pH to less than 3 using 6N HCl. This step is crucial for accurate test results, as certain preservatives or collection errors can affect the reliability of the test.
Limitations
The test requires a 24-hour urine specimen with appropriate preservative (6N HCl) to ensure stability and accuracy. Specimens collected without the correct preservative or with incorrect pH may be rejected. Furthermore, the test results can be influenced by improper collection techniques or incomplete 24-hour specimen collection. Boric acid or acetic acid should not be used as preservatives as they do not adequately stabilize the specimen for analysis. Additionally, medications or dietary factors that affect catecholamine levels may influence results, potentially leading to false positives or negatives.
Methodology
Mass Spectrometry
Biomarkers
LOINC Codes
- 9624-8
- 3122-9
- 11046-0
- 2232-7
- 2667-4
- 2668-2
- 2217-8
- 2218-6
- 9624-8
- 3122-9
- 11046-0
- 2232-7
- 2667-4
- 2668-2
- 2217-8
- 2218-6
Result Turnaround Time
6-9 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
60 mL aliquot
Minimum Volume
Not provided
Container
Plastic urine container with 30 mL 6N HCl
Collection Instructions
Preservative must be added to the container prior to the start of collection. Collect 24-hour urine. Mix well. Send 60 mL aliquot. Record total 24-hour urine volume on test request form. Final pH must be <5. Note: Do not use boric acid or acetic acid as a preservative.
Patient Preparation
See Catecholamines, Fractionated, Urinary Free, 24-Hour Urine [004176] and Vanillylmandelic Acid (VMA), 24-Hour Urine [004143].
Storage Instructions
Refrigerate
Causes for Rejection
Specimen with no preservatives; original container with pH >5; boric acid or acetic acid used as a preservative