Comparisons of plasma aldosterone and renin data between an automated chemiluminescent immunoanalyzer and conventional radioimmunoassays in the screening and diagnosis of primary aldosteronism

Abstract

Determining values of plasma renin activity (PRA) or plasma active renin concentration (ARC), plasma aldosterone concentration (PAC), and aldosterone-to-renin ratio (ARR) is essential to diagnose primary aldosteronism (PA), but it takes several days with conventional radioimmunoassays (RIAs). Chemiluminescent enzyme immunoassays for PAC and ARC using the Accuraseed® immunoanalyzer facilitated the determination, but relations between Accuraseed® immunoanalyzer-based and RIA-based values in samples of PA confirmatory tests and adrenal venous sampling remained to be elucidated. We addressed this issue in the present study. This is a prospective, cross-sectional study. ARC and PAC values were measured by the Accuraseed® immunoanalyzer in samples, in which PRA and PAC values had been measured by the PRA-FR® RIA and SPAC®-S Aldosterone kits, respectively. The relations between Accuraseed® immunoanalyzer-based and RIA-based values were investigated with regression analyses. The optimal cutoff of Accuraseed® immunoanalyzer-based ARR for PA screening was determined by the receiver operating characteristic analysis. After log-log transformations, linear relations with high coefficients of determination were observed between Accuraseed® immunoanalyzer-based and RIA-based data of renin and aldosterone. Following the PA guidelines of Japan Endocrine Society, Accuraseed® immunoanalyzer-based cutoffs were calculated from the regression equations: the basal PAC for PA screening >12 ng/dL, PAC for the saline infusion test >8.2 ng/dL, ARC for the furosemide-upright test <15 pg/mL, and ARR for the captopril challenge test >3.09 ng/dL per pg/mL. The optimal cutoff of Accuraseed® immunoanalyzer-based ARR for PA screening was >2.43 ng/dL over pg/mL not to overlook bilateral PA patients. The present study provided conversion formulas between Accuraseed® immunoanalyzer-based and RIA-based values of renin, aldosterone, and ARR, not only in basal samples but also in samples of PA confirmatory tests and adrenal venous sampling. Although validation studies are awaited, the present study will become priming water of harmonization of renin and aldosterone immunoassays.

State of the art: Lateral flow assays toward the point‐of‐care foodborne pathogenic bacteria detection in food samples

“…The ELISA has been the most generally applied format for immunoassays. ELISA has been generated from a vast search for substitutes to labeling of antigens or antibodies with radioisotopes for application in immunoradiometric techniques (Exner & Koutts, 2021) and radioimmunoassays (Tamura et al., 2021). The two‐site ELISA, also known as sandwich ELISA, has been used for bacteria's recognition in foodstuff (Kim et al., 2021).…”

Antibody Responses to BNT162b2 Vaccination in Japan: Monitoring Vaccine Efficacy by Measuring IgG Antibodies against the Receptor-Binding Domain of SARS-CoV-2

“…We utilized another laboratory test kit ( 33 ) for the Accuraseed automated immunoassay system (FUJIFILM Wako Pure Chemical Corporation) to develop a CLEIA method to measure RBD-IgG in serum samples. The Accuraseed is an automated immune analyzer based on a CLEIA method that combines antigen-antibody reaction and chemiluminescence reaction.…”

The spectrum of plasma renin activity and hypertension diseases: Utility, outlook, and suggestions

“…Despite the convenience and popularity of routine immunoassays, they suffer from several major drawbacks, including antibody storage stability, cross-reactivity, and low sensitivity (0.2 ng/ml/h) 60,61 ; therefore, the highly sensitive and specific ID-LC/MS/MS method using stable isotope-labeled internal standards for PRA measurement has been developed and recognized as an appropriate alternative. spiking recoveries of 93%-105%, the LOQ was 0.005 ng/ml/h, and the intra and inter-assay imprecision ranged from 1.6%-8.3% and 7.2%-9.4%, respectively.…”

“…Despite the convenience and popularity of routine immunoassays, they suffer from several major drawbacks, including antibody storage stability, cross‐reactivity, and low sensitivity (0.2 ng/ml/h) 60 , 61 ; therefore, the highly sensitive and specific ID‐LC/MS/MS method using stable isotope‐labeled internal standards for PRA measurement has been developed and recognized as an appropriate alternative. There are similarities in sample preparation procedures between present ID‐LC/MS/MS methods, generally including plasma incubation, sample extraction, and injection for LC–MS/MS analysis, and the main discrepancies existing in each step involve the components and concentration of protease inhibitors, sample extraction modes, parameter optimization, and equalization between different types of apparatuses.…”