PLASMA METANEPHRINE TEST

A plasma metanephrine test measures metanephrine and normetanephrine in the blood to detect catecholamine‑secreting tumors (pheochromocytoma and paraganglioma). It’s used to investigate unexplained high blood pressure and symptoms like headaches, sweating and palpitations, and to monitor for recurrence after treatment. Preparation often requires resting supine before the blood draw and avoiding certain medications or foods that can affect results.

The metanephrine test measures metanephrines (breakdown products of adrenaline and noradrenaline) in blood or urine to detect catecholamine-secreting tumors such as pheochromocytoma and paraganglioma. It’s used when patients have unexplained high blood pressure, episodes of headache, sweating or palpitations, and to monitor treatment or recurrence after tumor removal. Plasma free or 24-hour urinary fractionated measurements guide further imaging and management.

Costs vary by test type and location. Public health systems commonly cover metanephrine testing at point of care. In private labs, a 24‑hour urine metanephrine test typically ranges about $40–$200, while plasma free metanephrines commonly cost about $100–$400. Exact fees depend on the laboratory, city and insurance; check with your provider or lab for the current price.

High metanephrines suggest excess catecholamine production—often from a pheochromocytoma or paraganglioma—but false positives can occur from certain drugs, stress, illness, or improper collection. Repeat testing after stopping interfering medicines and under correct conditions; if still high, see an endocrinologist for imaging and specialist management. Treat high blood pressure promptly; genetic testing may be offered in confirmed cases.

Yes. Metanephrines (plasma free or 24‑hour urinary fractionated) are biochemical tumor markers used to detect and monitor catecholamine‑secreting tumors—pheochromocytomas and paragangliomas. Elevated metanephrine levels suggest these tumors and guide further imaging and management; testing is highly sensitive, so markedly raised values prompt confirmatory workup, while borderline results may need repeat sampling or interference review.

Normal plasma free metanephrine values depend on assay and posture. When sampled supine, metanephrine is typically <0.5 nmol/L and normetanephrine <0.9 nmol/L; seated reference limits are higher. Laboratories report their own cutoffs, so results must be interpreted against lab-specific ranges. Mild elevations warrant repeat testing and clinical evaluation for pheochromocytoma/paraganglioma. Medications and stress can raise levels.