CLINICAL VALIDATION OF THE NEW AUTOMATED ALDOSTERONE LIAISON XL ASSAY ON THE ADRENAL VEIN SAMPLING CONFIRMATORY TEST

Abstract

Objective: Measurement of aldosterone is the cornerstone in Primary aldosteronism (PA) workup, for both screening and final diagnosis (as confirmatory test). Albeit several automated aldosterone chemiluminescent assays have become recently available as reliable alternatives to the well-established radioimmunometric methods (RIA), little information is available on the diagnostic performance of the former methods using samples collected by adrenal vein sampling (AVS). AVS for aldosterone measurement is still considered the ‘gold standard’ procedure to differentiate aldosterone-producing adenoma (APA) and bilateral idiopathic hyperaldosteronism (IHA). This study was aimed to assess the clinical utility of the new Aldosterone Liaison XL assay for AVS sampling compared with a traditional RIA method. Design and method: The study population consisted of 12 patients (10 males and 2 females) undergoing AVS, Aldosterone was measured with RIA (DSL800, Beckman coulter), and Liaison XL (Diasorin). Samples were taken step by step from both adrenal veins, and the superior and inferior vena cava (upper and below renal vein). Results: Results of serum samples (n = 46) were analysed. The median values (2.5–97.5 percentiles) for RIA and Liaison XL were 289 ng/mL (58–48550 pg/mL) and 203 ng/mL (64–39689 pg/mL), respectively. The nonparametric regression of Passing & Bablok and the Spearman's correlation showed excellent performance for Liaison XL Aldosterone compared to RIA (Liaison XL = 0,48 x RIA + 30.5; r = 0.95, p < 0.001). In all patients the lateralization ratio with RIA were confirmed with Liaison XL method. (7 patients had IHA; APA were 2 right and 3 left, respectively) Conclusions: The rate of lateralization at AVS is identical when either RIA or LIAISON XL are used for aldosterone determination. We therefore conclude that the new Liaison XL Aldosterone is a suitable assay for the rapid quantification for the AVS procedure.