Endocrine Abstracts

Introduction: Primary Aldosteronism (PA) is the most common cause of secondary hypertension and is associated with increased risk of morbidity and mortality when compared to primary hypertension. We have developed a LC-MS/MS method for the measurement of aldosterone and related metabolites in early morning urine samples, to provide an alterative screening test for PA. This aims to streamline identification and subtyping of PA, particularly in patients with KCNJ5 mutations.

Method: Analysis of 18-hydroxycortisol, 18-oxocortisol, aldosterone, cortisol, 18-hydroxycortisosterone and tetrahydroaldosterone was performed in a single LC-MS/MS method on a Waters TQ-Absolute mass spectrometer. Steroids were deconjugated and extracted from early morning urine samples in a 96-well format. We assessed various deconjugation and extraction procedures.

Results: Liquid-liquid extraction (LLE) with ethyl acetate following an overnight enzyme deconjugation with aryl sulfatase/glucuronidase showed optimal recovery. The method demonstrated good recovery and minimal matrix effects.

Conclusion: We have developed an LC-MS/MS assay to measure aldosterone and related metabolites in early morning urine samples. This has clinical applications at providing an at-home screening test for PA, which could allow for early identification of PA subtypes. We hope to develop our in-house method further and aim to implement this approach in the future for the diagnostic work up of PA patients.