Also Known As
VMAU
Formal Name
Vanillylmandelic Acid, urine
This article was last reviewed on
This article waslast modified on 28 August 2019.
At a Glance
Why Get Tested?

To help diagnose or rule out a neuroblastoma and to monitor the effectiveness of treatment

When To Get Tested?

When your child has symptoms consistent with neuroblastoma

Sample Required?

A 24-hour urine sample is preferred; sometimes a random urine sample is acceptable

Test Preparation Needed?

Though the test is affected by caffeine and certain drugs this is not usually relevant in children.

On average it takes 7 working days for the blood test results to come back from the hospital, depending on the exact tests requested. Some specialist test results may take longer, if samples have to be sent to a reference (specialist) laboratory. The X-ray & scan results may take longer. If you are registered to use the online services of your local practice, you may be able to access your results online. Your GP practice will be able to provide specific details.

If the doctor wants to see you about the result(s), you will be offered an appointment. If you are concerned about your test results, you will need to arrange an appointment with your doctor so that all relevant information including age, ethnicity, health history, signs and symptoms, laboratory and other procedures (radiology, endoscopy, etc.), can be considered.

Lab Tests Online-UK is an educational website designed to provide patients and carers with information on laboratory tests used in medical care. We are not a laboratory and are unable to comment on an individual's health and treatment.

Reference ranges are dependent on many factors, including patient age, sex, sample population, and test method, and numeric test results can have different meanings in different laboratories.

For these reasons, you will not find reference ranges for the majority of tests described on this web site. The lab report containing your test results should include the relevant reference range for your test(s). Please consult your doctor or the laboratory that performed the test(s) to obtain the reference range if you do not have the lab report.

For more information on reference ranges, please read Reference Ranges and What They Mean.

What is being tested?

Vanillylmandelic acid (VMA) is one of the metabolites of the catecholamines adrenaline (epinephrine) and noradrenaline (norepinephrine), hormones produced in the adrenal glands. This test measures the amount of VMA that is excreted into the urine, typically over a 24-hour period, to detect excess catecholamine production.

Neuroblastomas can produce large amounts of catecholamines resulting in greatly increased concentrations of the hormones and their metabolites.Neuroblastomas are the second most common solid tumour in childhood after brain cancer. Up to 90 per cent of cases occur in children under the age of five. Once detected, many neuroblastomas can be successfully treated.

How is the sample collected for testing?
For a 24-hour urine collection, all of the urine produced during a 24-hour period should be collected into a container and saved. It is important that the sample be refrigerated during this time period. A single urine sample is collected for a random urine test.

Is any test preparation needed to ensure the quality of the sample?
This test is affected by caffeine, certain drugs, and stresses. Though this is less likely in children it is important to inform your healthcare professional of any medications being given, including herbal supplements and over-the-counter products, and to follow any instructions provided for things to withhold before sample collection.

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Common Questions
  • How is it used?

    The vanillylmandelic acid (VMA) test is primarily used to detect and rule out neuroblastomas in children with an abdominal mass or other symptoms suggestive of the disease.

  • When is it requested?

    VMA testing is requested when a doctor either suspects that a child has a neuroblastoma or wants to rule out the possibility.

    The VMA test may also be requested when a child has been treated for a neuroblastoma and requested periodically to monitor for recurrence.

  • What does the test result mean?

    Since the VMA test is sensitive to many outside influences false positives may be seen. When a person has large amounts of VMA in the urine it is an indication that further investigation is necessary.

    If a child is being treated for a neuroblastoma, then decreasing VMA concentrations indicate a response to treatment. If a VMA concentration is initially normal and then increases in a person who has had a previous neuroblastoma, then it is likely that the tumour is recurring.

    About 90% of children with a neuroblastoma will produce excess VMA and homovanillic acid. Therefore a normal result makes a neuroblastoma less likely, but it cannot be ruled out.

  • Is there anything else I should know?

    The amount of VMA produced does not necessarily correspond to the size of the tumour. The total amount of VMA produced will tend to increase, however, as the tumour increases in size.

    A variety of medications can interfere with VMA testing, including insulin but please discuss this with the doctor before withholding any medications.

  • Why do I have to collect my urine for 24 hours?

    The reason that you need to collect the urine over a 24-hour period is because the amount of VMA excreted in the urine changes during the course of a day. By collecting all urine for 24 hours, the amount of VMA measured can be averaged over the entire day and will give a better indication of whether levels are increased or not.

  • Can this test be done at my doctor's surgery?

    No, this test requires specialised equipment and must be performed in a laboratory. Not every laboratory will perform this assay; in some cases, your sample will need to be sent to a reference laboratory.

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