Sample Requirements:
SST and EDTA tubes; upright 2 hrs before draw
Purpose:
Evaluates kidney function, renin-aldosterone ratio, and electrolytes in patients with hypertension. Assesses secondary causes of high blood pressure.
Reference Range:
Aldosterone: 4–31 ng/dL; Renin: 0.5–4.0 ng/mL/hr; Na: 135–145 mmol/L