Initial Laboratory Tests for Patients with Persistent Hypertension and Acanthosis Nigricans

Clinical Indicators and Screening

The American Diabetes Association recommends screening for type 2 diabetes in patients with signs of insulin resistance, specifically listing acanthosis nigricans as a key clinical indicator 1
Acanthosis nigricans is a dermatologic marker of hyperinsulinemia and insulin resistance, and the most appropriate initial laboratory test is fasting blood glucose (or HbA1c) to screen for insulin resistance and diabetes mellitus type 2 1

The American Heart Association recommends paired morning plasma aldosterone and plasma renin activity for patients with resistant hypertension, defined as BP >140/90 mmHg despite optimal doses of at least three antihypertensive drugs including a diuretic 2
Measurement of plasma or urinary metanephrines is indicated for screening pheochromocytoma, but this condition presents with episodic symptoms and labile hypertension—not persistent hypertension with acanthosis nigricans 2, 4

Basic metabolic profile (sodium, potassium, creatinine, eGFR) should be included in the comprehensive evaluation to assess for kidney disease and electrolyte abnormalities 2, 4
Lipid profile should be included since insulin resistance is associated with dyslipidemia 1, 4
Urinalysis with albumin-to-creatinine ratio should be included to detect early kidney damage 4

The combination of hypertension, acanthosis nigricans, and likely obesity represents metabolic syndrome, which affects 40% of hypertensive patients and requires lifestyle intervention alongside pharmacologic management 4