What is being analysed here?

Plasma metanephrines is being analysed here. They are substances measured in the blood. These are metabolites of catecholamines, such as adrenaline (epinephrine) and noradrenaline (norepinephrine).

Catecholamines are produced in the adrenal medulla and also by cells in the sympathetic nervous system. These hormones play a crucial role in stress response and the regulation of blood pressure, heart rate, and metabolism.

What does the result mean?

The analysis of plasma metanephrines is primarily used to diagnose or rule out the presence of two rare types of tumours: pheochromocytoma, which is an adrenal gland tumor that produces large amounts of catecholamines, and paraganglioma, a tumour that occurs outside the adrenal gland and also releases catecholamines.

Why is this analysis carried out?

The plasma metanephrines analysis is performed in the following cases:

• Suspected catecholamine-releasing tumours: When there are signs or symptoms such as sudden blood pressure elevation, headaches, palpitations, sweating, tremors, and facial flushing.
• Genetic predisposition: If there is a risk of developing pheochromocytoma or paraganglioma.
• Postoperative follow-up: To detect recurrence after removing one of these tumours.
• Incidental finding: When an adrenal tumour is accidentally detected on imaging.

When is the analysis performed?

The analysis is recommended in the previously mentioned cases. It is essential to follow pre-sample extraction instructions, as certain medications, foods, and stress can affect the results.

What sample is required?

Plasma metanephrines determination is performed from a sample of venous blood from the arm. The most common position for extraction is the supine position (lying face up).

What are considered to be normal values?

Normal plasma metanephrine values vary depending on the laboratory and the technique used. 

What do altered values indicate?

Elevated metanephrines may indicate the presence of a pheochromocytoma or paraganglioma. However, a comprehensive evaluation by a physician is required to confirm the diagnosis.