This specialized diagnostic technique is critical for assessing patients with suspected primary aldosteronism. By drawing blood directly from the adrenal veins, clinicians can determine the source of excess hormone production. Adrenal venous sampling distinguishes between unilateral and bilateral adrenal involvement, determining whether surgery or medical therapy is most effective. As the gold standard for accurate localization, it is particularly useful when imaging studies are inconclusive, ensuring that patients receive tailored and effective care.