This prospective, single-center observational study aims to evaluate whether a steroid-based screening method can more accurately identify Primary Aldosteronism (PA) in hypertensive patients who remain on their usual antihypertensive medications, compared with the conventional aldosterone-to-renin ratio (ARR). PA is a common, potentially curable subtype of secondary hypertension that carries increased cardiovascular risk when undiagnosed or untreated. However, current screening protocols recommend medication washout or switching to minimally interfering drugs, which may pose safety concerns and add complexity. In this study, approximately 515 participants (ages 18-75) with diagnosed hypertension and on at least one interfering antihypertensive drug (such as ACE inhibitors, ARBs, beta-blockers, diuretics, or calcium channel blockers) will be enrolled at the Department of Endocrinology, The First Affiliated Hospital of Chongqing Medical University. Each participant will undergo two rounds of blood sampling-first while continuing their usual antihypertensive regimen (the on-medication state) and second following a standardized washout/switch period (the standard state), if medically feasible. At both stages, levels of plasma aldosterone, renin, and a broad panel of adrenal steroid hormones will be measured by liquid chromatography-tandem mass spectrometry. By comparing diagnostic performance (e.g., sensitivity, specificity, and area under the receiver operating characteristic curve) of the steroid-based screening versus the ARR, the study seeks to determine whether steroid profiling improves accuracy under real-world treatment conditions. Findings may help refine PA screening strategies, reduce the need for extensive medication adjustments, and contribute to better clinical management of hypertension.