The Spread of 10 Minutes Measurement of Aldosterone and Active Renin Concentrations May Increase the Number of the Patients Diagnosed As Primary Aldosteronism -the Accuracy Analysis and the Clinical Validation of Fully Automated Chemiluminescence Immunoassays-

Presentation Number: SUN 515
Date of Presentation: April 2nd, 2017

Fumitoshi Satoh*1, Ryo Morimoto2, Yoshikiyo Ono2, Yuta Tezuka1, Kei Omata1, Masahiro Nezu2, Yoshitsugu Iwakura2, Yasuhiro Igarashi2, Masataka Kudo2, Sachiko Yamamoto3, Celso E. Gomez-Sanchez4 and Sadayoshi Ito2
1Tohoku University Graduate School of Medicine, Sendai, Japan, 2Tohoku University Hospital, Sendai, Japan, 3Wako Pure Chemical Industries, Ltd., Osaka, Japan, 4University of Mississippi Medical Center, Jackson, MS

Abstract

Context: The measurement of plasma aldosterone concentration (PAC) and renin activity (PRA) or active renin concentration (ARC) is clinically important not only for detection of primary aldosteronism (PA) but also for the selection of antihypertensive agents to treat patients successfully. However, it has taken approximately 7 days for clinicians to get the results. Of late, we developed the novel rapid non-RIA assays of PAC and ARC, which can be measure in 10 minutes.

Objective: This study is intended to investigate the accuracy of the new measurements and to perform the clinical validation of their ability of differentiating patients with primary aldosteronism from those with essential hypertension.

Design and Setting: Both PAC and ARC in 25 μL plasma sample were simultaneously measured by chemiluminescent enzyme immunoassay (CLEIA) system machine, “Accuraseed “with their specific monoclonal antibodies, using the automatically washable antibody-immobilized magnetic particles with very quick aggregation and dispersion, “MAGRAPID”. We retrospectively compared PAC and ARC measured by Accuraseed with those by conventional RIA and PAC by LC-MS/MS in 222 patients with aldosterone producing adenoma (APA, n=75), bilateral idiopathic hyperaldosteronism (IHA, n=50) and essential hypertension (EH, n=97). We examined the accuracy of Accuraseed by Bland-Altman plot analysis.

Results: Measurements of PAC by Accuraseed were significantly correlated with those of LC-MS/MS (Spearman's r = 0.988, p< 0.0001). Measurements of PAC by RIA were also correlated with those of LC-MS/MS (Spearman's r = 0.963, p< 0.0001) and the degree of correlation was better in the comparison between Accuraseed and LC-MS/MS. Bland-Altman plot analysis revealed the bias of 13.7 and the limits of agreement were 10.85 and 16.55 with 95% confidence interval when comparing Accuraseed and LC-MS/MS. The comparison between RIA and LC-MS/MS revealed the bias of 33.4 with the limits of agreement of 15.2 and 51.5. There was the smaller systemic error in Accuraseed-PAC when compared to RIA-PAC. Measurements of ARC by Accuraseed were significantly correlated with those by RIA (Spearman's r = 0.930, Y= 0.960 X + 1.128, p< 0.0001). The lower detection limit of CLEIA-ARC was 0.25 pg/mL and much lower than that of RIA-ARC (2 pg/mL). Bland-Altman plot analysis revealed that the bias of -0.97 and the limits of agreement were -1.087 and -0.8671 with 95% confidence interval when comparing Accuraseed-ARC and RIA-ARC. Accuraseed-ARC were also correlated with those of RIA-PRA (Spearman's r = 0.912, Y = 4.082 X + 0.549, p< 0.0001). By using Accuraseed measured PAC and ARC, we can successfully diagnose 125 PA patients retrospectively.

Conclusions: Recently developed Accuraseed measured PAC and ARC can be a clinically reliable. Using this method might be expected to contribute better throughput and cost-effectiveness in diagnosis of PA.

 

Nothing to Disclose: FS, RM, YO, YT, KO, MN, YI, YI, MK, SY, CEG, SI