Description

Test Name: 24-Hour Urine for Metanephrines
Sample Required: 24-hour urine collection
Fasting Required: ❌ Not required (but some food & medicines to be avoided)
Report Time: 2–4 days (depends on lab)

Overview:
This test measures the levels of metanephrines (substances made from adrenaline) in urine collected over 24 hours. It helps in detecting rare tumors like pheochromocytoma and paraganglioma, which cause very high blood pressure.

Why is this test important?

• Detects pheochromocytoma & paraganglioma (tumors of adrenal glands)

• Helps find cause of uncontrolled high BP, sweating, fast heartbeat, headaches

• Monitors patients after treatment or surgery for these tumors

Preparation:

• You will need to collect all urine for 24 hours in a special container given by the lab.

• Avoid certain foods (bananas, caffeine, chocolates, vanilla) and some medicines (discuss with doctor).

This test gives important clues for unexplained or resistant high blood pressure.

linical Significance:
Metanephrines (metanephrine and normetanephrine) are metabolites of catecholamines (epinephrine, norepinephrine). Measurement in a 24-hour urine sample provides a sensitive diagnostic tool for pheochromocytoma and paraganglioma (PPGLs). These tumors often present with paroxysmal or sustained hypertension, headaches, sweating, and palpitations.

Reference Ranges (may vary by lab):

• Metanephrine: <350 µg/24 hr

• Normetanephrine: <600 µg/24 hr

• Elevated levels suggest catecholamine-secreting tumor.

Indications:

• Evaluation of paroxysmal or resistant hypertension

• Screening for pheochromocytoma/paraganglioma in symptomatic patients

• Follow-up after tumor removal or therapy

• Assessment in patients with genetic predisposition (MEN2, VHL, NF1 syndromes)

Preparation & Precautions:

• No fasting required, but avoid foods high in catecholamines (bananas, coffee, tea, chocolate, vanilla, citrus fruits) for at least 48 hours.

• Avoid certain drugs (tricyclic antidepressants, labetalol, levodopa) if possible, under physician guidance.

• Patient must collect all urine for 24 hours in a container provided with preservative (acid).

Turnaround Time:

• Reports usually available in 2–4 working days.