Why is this analysis done?

Metanephrines analysis is performed to diagnose and monitor conditions related to the adrenal glands, particularly pheochromocytoma and paraganglioma. These tumours can lead to excessive production of catecholamines, which are broken down into metanephrines in the body. Detecting elevated levels of metanephrines can aid in the early detection and management of these conditions.

When should the analysis be done?

This analysis is typically recommended when a patient presents symptoms suggestive of pheochromocytoma or paraganglioma, such as high blood pressure, palpitations, headaches, and sweating. It may also be ordered as a follow-up to confirm diagnosis or monitor treatment effectiveness.

What sample is required?

A 24-hour urine collection is the preferred sample for metanephrines analysis. This method provides a more accurate reflection of the body's metanephrine levels compared to a single spot urine sample.

Is any prior preparation necessary?

Yes, certain medications and foods can interfere with the test results. It's essential to inform your doctor about any medications you're taking, particularly those that affect blood pressure or contain catecholamines. Additionally, avoiding certain foods and beverages, such as coffee, tea, chocolate, and bananas, for a specified period before the test may be necessary.

How is it used?

Metanephrines analysis helps in the diagnosis of pheochromocytoma and paraganglioma by measuring the levels of metanephrine and normetanephrine in the urine. Elevated levels of these substances suggest the presence of these tumours and aid in confirming the diagnosis.

What are the normal values?

The normal range for metanephrine and normetanephrine in a 24-hour urine collection varies slightly depending on the laboratory performing the analysis. However, generally, the normal values are:

• Metanephrine: Less than 350 µg/24h
• Normetanephrine: Less than 600 µg/24h

What does having altered values mean?

Elevated levels of metanephrines in the urine suggest an overproduction of catecholamines, which can indicate the presence of a pheochromocytoma or paraganglioma. These tumours are typically benign but can cause severe hypertension and cardiovascular complications if left untreated. Conversely, normal levels of metanephrines indicate the absence of significant catecholamine production and are consistent with a negative diagnosis for these conditions.

Normal values: