The Plasma Metanephrines test measures metanephrines in the blood, which are breakdown products of adrenaline and noradrenaline. These hormones are released by the adrenal glands and play a key role in regulating blood pressure, heart rate, and the body’s response to stress.

This test is primarily used to investigate suspected pheochromocytoma or paraganglioma, rare tumours that produce excess catecholamines. Such tumours can cause episodic or persistent symptoms including high blood pressure, headaches, palpitations, sweating, and anxiety.

Plasma metanephrines are considered a sensitive marker for these conditions because metanephrines are produced continuously, even when hormone release is intermittent.

Accurate testing requires careful preparation and interpretation. Certain medications, stress, and posture can influence results, which is why results are reviewed in conjunction with clinical history and further testing if required.

Early detection of catecholamine-producing tumours is important, as appropriate treatment can significantly improve outcomes.