Metanephrines Urine Test

Your healthcare practitioner will first order a metanephrine blood test if they suspect that you have an adrenal gland tumour. However, if the blood test results show less than two-fold elevation in metanephrine or low suspicion of adrenal gland tumour like pheochromocytoma, they will order the metanephrine urine test. 

This test is considered more specific than the blood test because it gives an average of metanephrine levels that otherwise fluctuate throughout the day.

Symptoms associated with adrenal tumours and hence elevated metanephrine levels are as follows:

• Palpitation
• Tremor
• Sweating
• Severe headache
• High blood pressure

Avoid drinking caffeinated beverages such as coffee, tea or cola before or during the test. Avoid vigorous exercise and any emotional or physical stress before or during the test. 

Inform your doctor if you are taking any prescribed, non-prescribed, legal or illicit drugs. Drugs such as tricyclic antidepressants, labetalol, sotalol and amphetamines can affect the test results. Your doctor may ask you to stop taking them one week before the test. However, do not skip any medicines on your own.

A sterile urine sample is needed for this test. You will be provided with a special container for collecting the sample. Here is the right way to collect a 24-hour urine sample:

• Wash your hands and clean your genital area using a cleansing pad.
• Sample collection for a 24-hour urine test usually begins in the early morning. However, the first urine is not collected. Empty your bladder in the morning and note the timing.
• For the next 24 hours, collect the urine sample each time you urinate.
• Make sure you refrigerate the sample until it is given to the lab for testing.
• Once the sample is collected, label it with your name and date and submit it to the lab for testing.

Always wash your hands after urination to avoid any chances of infection. Make sure you stay at home for 24 hours during the test for proper storage of the urine.

Normal results:

Normal results mean that you do not have adrenal gland tumour. These levels are as follows:

• Metanephrine: 24-96 mcg/24 hours
• Normetanephrine: 75-375 mcg/24 hours
• Total metanephrine: less than or equal to 1300 mcg/24 hours

Abnormal results:

High levels of metanephrine:

A high level of metanephrines indicates that you may have an adrenal gland tumour such as pheochromocytoma or paraganglioma. If the levels are elevated even after the treatment for tumour, it indicates that either the tumour is recurring or the treatment was ineffective.

Here is what an abnormal result may mean: 

• <2 times the normal level: low chances of having pheochromocytoma or paraganglioma.
• >2 times the normal level: High chances of having pheochromocytoma or paraganglioma.

It is important to note that these levels may be different for different laboratory. Please check with your healthcare practitioner before concluding that you have a tumour.

A false-positive result is sometimes observed in a metanephrine urine test. Some of the reasons for false-positive results are:

• Obstructive sleep apnoea
• Emotional or physical stress
• Eating bananas
• Smoking

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.