Urinary tetrahydroaldosterone excretion decreased with age at a rate of 1.25 nmol/24h per year (R2=0.096), while aldosterone excretion showed significant decline in older age groups with median levels dropping from 31.2 nmol/24h (<30 years) to 16.7 nmol/24h (70-79 years).
Observational (n=265)
Yes
Does the developed LC-MS/MS method provide valid measurements and reference intervals for urinary aldosterone and tetrahydroaldosterone?
The validated LC-MS/MS assay and established reference intervals enable standardized urinary aldosterone profiling to improve the biochemical diagnosis of primary aldosteronism.
Abstract Objectives Primary aldosteronism (PA) is a common cause of secondary hypertension. To address the specificity limits of immunoassays, we developed and validated an LC-MS/MS method for urinary aldosterone and tetrahydroaldosterone and established method-matched reference intervals for excretion in 24 h urine. Methods Urinary aldosterone, tetrahydroaldosterone and their glucuronidated metabolites were extracted in the presence of internal standards using offline solid-phase extraction (SPE), followed by enzymatic hydrolysis to release the glucuronidated fraction. Subsequently, aldosterone and tetrahydroaldosterone were analyzed by online SPE in combination with LC-MS/MS. Reference intervals were established based on 24 h urine samples from 265 individuals participating in the Lifelines Cohort study. Results Intra- and inter-assay imprecision ranged from 2.0–12.3 % for aldosterone, and 1.3–6.3 % for tetrahydroaldosterone. The lower limits of quantification were 0.44 nmol/L and 0.10 nmol/L, respectively. Recoveries ranged from 97–106 %, calibration was linear, with correlation coefficients greater than 0.999, and no carry-over was observed. Total aldosterone concentrations measured by LC-MS/MS were consistently higher than those obtained by radioimmunoassay. In the reference population, 24 h urinary excretion ranged from 5.4–76.7 nmol/24 h for aldosterone and 21.4–269.9 nmol/24 h for tetrahydroaldosterone. Conclusions This validated LC-MS/MS assay, together with a method-matched normative dataset, enables standardized urinary aldosterone profiling and defines reference intervals that will help improve the interpretability of results in the biochemical diagnosis of PA.
Kooi et al. (Sun,) conducted a observational in healthy adults from a population-based cohort in the North of the Netherlands without medication use or low-sodium diet (n=265). urinary aldosterone and tetrahydroaldosterone measurement via LC-MS/MS with enzymatic hydrolysis was evaluated on 24-hour urinary aldosterone and tetrahydroaldosterone excretion stratified by age with age-stratified reference intervals. Urinary tetrahydroaldosterone excretion decreased with age at a rate of 1.25 nmol/24h per year (R2=0.096), while aldosterone excretion showed significant decline in older age groups with median levels dropping from 31.2 nmol/24h (<30 years) to 16.7 nmol/24h (70-79 years).