What is the Plasma Metanephrines test?

The Plasma Metanephrines test measures metanephrine and normetanephrine, which are breakdown products of adrenaline (epinephrine) and noradrenaline (norepinephrine). These hormones are produced by the adrenal glands and play a key role in stress response and blood pressure regulation.

Unlike direct adrenaline measurements, metanephrines are more stable in the blood, making this test highly sensitive for detecting adrenal hormone overproduction. It is considered one of the most reliable screening tests for pheochromocytoma and related adrenal disorders.

Why do I need a Plasma Metanephrines test?

Excess adrenal hormone release can cause sudden or persistent symptoms and may be difficult to diagnose without targeted testing.

You may need this test if you experience:

• Persistent or episodic high blood pressure

• Severe headaches

• Palpitations or rapid heartbeat

• Excessive sweating

• Anxiety or panic-like symptoms

• Tremors

• Flushing

• Adrenal mass seen on imaging

• Unexplained cardiovascular symptoms

The test helps determine whether symptoms are driven by abnormal adrenal hormone activity.

Benefits of the test

1. Highly sensitive adrenal screening test
   Detects subtle hormone excess.

2. Gold-standard test for pheochromocytoma screening
   Recommended in adrenal assessment pathways.

3. More reliable than adrenaline testing
   Metanephrines are more stable markers.

4. Explains unexplained hypertension
   Especially when blood pressure is difficult to control.

5. Supports investigation of adrenal tumours
   Helps guide further imaging and evaluation.

6. Simple blood-based testing
   Requires only one blood sample.

7. Widely used in endocrine practice
   Standard test for adrenal hormone disorders.

8. Reduces diagnostic uncertainty
   Helps rule in or out serious adrenal conditions.

Step-by-step: How we offer testing

Clinic-based testing (UK-wide)

• Choose your nearest UK clinic

• Attend your appointment

• Blood sample taken after a period of rest

• Sample sent to the laboratory

• Results are issued once analysis is complete

Home or hotel visit (+£60, UK-wide)

• Mobile phlebotomist attends your location

• Blood sample taken with resting conditions

• Sample securely transported to the laboratory

Pre-test conditions (resting, posture, and medication review) may be advised for accurate results.

Your results explained

Low / normal levels

• Metanephrines within reference range

• UK standard (typical):

  • Metanephrine: <0.50 nmol/L

  • Normetanephrine: <0.90 nmol/L

• Suggests no evidence of adrenal hormone excess

Mildly elevated levels

• Slightly raised metanephrines

• May be influenced by stress, posture, or medications

• Often requires repeat testing or further evaluation

High levels

• Significantly elevated metanephrines

• Well above reference range

• Strongly suggestive of pheochromocytoma or adrenal hormone overproduction

Results should always be interpreted alongside clinical symptoms and imaging where appropriate.