RAAS Activation Index (Plasma Renin Activity) Calculator

RAAS Activation Index (Plasma Renin Activity): Explanation and Clinical Context The RAAS Activation Index reflects the activity of the renin–angiotensin–aldosterone system (RAAS), which plays a crucial role in regulating blood pressure, sodium, and fluid balance. Plasma Renin Activity (PRA) measures the enzymatic activity of renin, expressed in ng/mL/h, which indicates how strongly the RAAS system is activated. Low PRA may suggest suppressed RAAS activity due to volume expansion or high sodium intake, whereas high PRA reflects RAAS overactivation, commonly seen in conditions like heart failure, hypertension, or renal artery stenosis.

Monitoring RAAS activation helps guide clinical decisions for RAAS-targeted therapies, such as ACE inhibitors, ARBs, or mineralocorticoid receptor antagonists.