Elevated Normetanephrines

An increased concentration of normetanephrine above the normal reference range (plasma: <0.90 nmol/L or ≤148 pg/mL; urine: 103-646 μg/24 hours), reflecting increased norepinephrine metabolism and excessive sympathetic-adrenal activity.

Causes

• Catecholamine-secreting tumors

  • Pheochromocytoma

  • Paraganglioma

• Medications

  • Tricyclic antidepressants (TCA)

  • Serotonin-norepinephrine reuptake inhibitors (SNRI)

  • β-blockers

  • α-blockers

  • Calcium channel blockers

  • Amphetamines

  • Cocaine

• Physiological and stress-related causes

  • Severe physical or emotional stress

  • Sepsis

  • Obstructive sleep apnea

  • Acute illness

  • Major surgery

• Substance withdrawal: Alcohol, sympathomimetic