Which study will the nurse prepare to monitor that best screens for an endocrine tumor presenting with hypertension?

• A. Thyroglobulin
• B. Catecholamine
• C. Vanillylmandelic acid
• D. Metanephrine

Answer: (D)

Endocrine tumors that cause high blood pressure are often pheochromocytomas, which release catecholamines. Metanephrine is a stable metabolite of these catecholamines that the tumor continuously produces, so its levels in plasma or urine provide a highly sensitive and reliable screen for pheochromocytoma. Metanephrine testing can detect the presence of excess catecholamine activity even when episodic symptoms aren’t occurring, making it the best screening choice.

In contrast, vanillylmandelic acid is a less sensitive and specific marker and can be influenced by diet and other factors. Measuring catecholamines directly can be variable due to stress, posture, or recent activity. Thyroglobulin is related to thyroid cancer, not adrenal tumors.