Intraindividual variability of aldosterone and the aldosterone-to-renin ratio detected by LC-MS/MS and their impact factors in patients with hypertension.

CONTEXT: Previous studies reported that plasma aldosterone concentration (PAC) and aldosterone-to-renin ratio (ARR) exhibit high intraindividual variability among hypertensive patients, but analyses of their variability and impact factors measured by liquid chromatography with tandem mass spectrometry (LC‒MS/MS) and under standard conditions are lacking. DESIGN AND SETTING: This prospective cohort study was conducted in a tertiary hospital in China. A total of 120 inpatients with hypertension, including 80 patients with primary aldosteronism(PA) and 40 patients with essential hypertension(EH), who underwent PA screening twice on different days were included. RESULTS: The coefficients of variation (CVs) for PAC and ARR in the PA group were greater than those in the group without PA (PAC: 30.44% vs. 14.30%, P < 0.05; ARR: 54.44% vs. 29.75%, P < 0.05). The proportion of single PAC below the 7.5ng/dl was 41.25% and single ARR below the 15 ng/dL: ng/mL· h was 42.50%. The repeated ARR measurement demonstrated the highest diagnostic accuracy (AUC 0.890), surpassing both the first (AUC 0.856) and second single measurements (AUC 0.812, P < 0.001). CONCLUSIONS: Under standardized conditions, our study reveals significant intraindividual variability in LC-MS/MS-measured PAC/ARR, associated with PAC levels and PA. We recommend repeated ARR testing for PA detection using LC‒MS/MS to reduce diagnostic omissions.