Vanillyl Mandelic Acid (VMA) urine test

This test is primarily ordered for the detection of neuroblastoma. Neuroblastoma is a tumour that forms in immature nerve cells (neuroblasts) in the adrenal glands, spinal cord, neck or chest. This tumour is commonly seen in young children. 

A VMA test may be ordered if the doctor sees the following symptoms of neuroblastoma in a child:

• Abnormal swelling or mass in the abdomen, neck or chest
• Bone pain
• Painless, bluish lumps under the skin
• Trouble breathing
• Bulging eyes
• Dark circles around the eyes
• Weakness of arms or legs

Other symptoms seen less commonly in neuroblastoma are:

• Fever 
• High blood pressure
• Enlarged lymph nodes
• Easy bruising and bleeding
• Feeling tired
• Droopy eyelids
• Jerky muscle movements
• Uncontrolled eye movements

Also, this test may be ordered periodically after the treatment of neuroblastoma to monitor for recurrence of the condition.

In people with high blood pressure that does not respond to treatment, a doctor may order this test to check for an adrenal gland tumour called pheochromocytoma. 

This test is usually performed along with other tests, such as 24-hour urine catecholamines and metanephrines (other by-products of catecholamine breakdown).

No fasting is required before this test. Your doctor may ask you to avoid consumption of tobacco, tea, coffee, alcohol, citrus fruits, banana and vanilla for three days before the test, as these may interfere with the test results. You may also be advised to avoid stress and excessive physical activity during the testing period. 

Inform your doctor if you are taking any prescription or non-prescription medicines or any supplements, as these may interfere with the test results. He/she may advise you to discontinue certain drugs at least three days before the test, as they may alter the test results. 

Drugs which may increase VMA levels include:

• Levodopa
• Lithium
• Nitro-glycerine 
• Caffeine
• Epinephrine

Drugs which may decrease VMA levels include:

• Phenothiazines
• Disulfiram
• Monoamine oxidase (MAO) inhibitors 
• Imipramine
• Reserpine

Do not discontinue any medication on your own.

A 24- hour urine sample is needed for this test. The laboratory will provide a container for collecting the sample. It is best to begin sample collection in the morning. Here is the right way to collect a 24-hour urine sample:

• Discard the first urine of the day, but note the time as the beginning of the 24-hour collection period.
• Collect all the urine over the next 24 hours in the container provided.
• Keep the urine container in the refrigerator or on ice throughout the collection period.
• Ensure that the urine is not contaminated with faeces or toilet paper.
• After the collection process is over, label the container and deliver it on ice to the laboratory as soon as possible.

This test may also be done on a random urine sample (single sample collected any time during the day) in children below 15 years of age.

Normal results:

The daily excretion of VMA increases with age, irrespective of gender. Normal values for VMA in 24-hr urine, according to the age group, are as follows:

In a random urine sample taken from children younger than 15 years of age, normal values of VMA are reported as follows:

Abnormal results:

Increased VMA levels may be seen in the following conditions:

• Severe stress
• Acute anxiety
• Ganglioneuroma
• Neuroblastoma
• Ganglioblastoma
• Pheochromocytoma

Vigorous exercising, starvation and stress may also increase VMA levels. Alkaline urine and uraemia may cause falsely decreased levels of VMA. Hence, share your complete medical history with your doctor so that your results can be interpreted accurately.

Disclaimer: All results must be clinically correlated with the patient’s complaints to make a complete and accurate diagnosis. The above information is provided from a purely educational point of view and is in no way a substitute for medical advice by a qualified doctor.