Abstract Body: Introduction:
Uncontrolled hypertension, defined as persistently elevated blood pressure despite antihypertensive therapy, arises from a spectrum of etiologies that include nonadherence, suboptimal pharmacologic regimens, secondary hypertension, and pathophysiological resistance mechanisms. Secondary causes - such as primary aldosteronism (PA) - remain frequently underdiagnosed due to the lack of efficient diagnostic tools. The multifactorial nature of uncontrolled hypertension underscores the critical medical need for advanced, versatile diagnostic platforms capable of stratifying patients according to underlying pathophysiology. The ALDO+ test (previously RAAS-Triple A) utilizes equilibrium levels of Ang I, Ang II, and aldosterone levels together with derived angiotensin-based biomarkers (AA2-Ratio, Q-RA and Q-ACE) in a precision diagnostic approach to stratify uncontrolled hypertensive patients. We report here the development and clinical validation of an algorithm combining PA screening with pharmacologic drug efficacy monitoring.

Methods/Results:
Reference ranges were derived from the Cooperative Health Research in South Tyrol (CHRIS) study (N=2105, N=1936 on anti-hypertensive drugs). Serum samples were analyzed using a validated LC-MS/MS method (ALDO+ Kit, CE-IVD, aTENSION.life). Treatment adherence was determined by measuring serum drug levels by LC-MS/MS. RAAS biomarker cut-offs for drug efficacy were determined by ROC analysis based on serum drug detection as gold standard for adherence. ACE inhibitors suppressed the Ang II to Ang I ratio (Q-ACE), while ARBs were linked to increased Ang II in most patients. Cut-offs for efficient ACE inhibition (Q-ACE < 1.2) and ARB efficacy (Ang II > 109.6 pM) were combined with a previously established PA screening cut-off using the aldosterone to Ang II ratio (AA2-Ratio > 3.9, Sensitivity: 97%; Specificity: 81%). The resulting algorithm was further applied to a cumulative cohort of > 2000 consecutive hypertensive patients from Austrian specialized centers between 2021 and 2025 and diagnostic outcomes were compared between the two cohorts.

Conclusions:
ALDO+ profiling is an effective single-test tool for the screening of PA in uncontrolled hypertensive patients on standard therapy, further providing treatment-relevant insights into pharmacologic efficacy of RAAS blockers. This work supports ALDO+ as a transformative tool for detecting multiple causes of uncontrolled hypertension in clinical routine.