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Background: Examination of aldosterone to Renin Ratio (ARR) and plasma aldosterone concentration (PAC) or 24-h urinary aldosterone excretion (24-h UALD) was the necessary tests in confirmatory tests for primary aldosteronism (PA). We developed a combined liquid chromatography-tandem mass spectrometry method (LC-MS/MS) for plasma renin activity (PRA), PAC, and angiotensin II (Ang II) and investigated their reference intervals (RIs) in northern Chinese Han population. The RIs of 24-h UALD excretion were also studied using LC-MS/MS., Methods: A total of 309 healthy volunteers were recruited in 3 cities in China. PRA, PAC, Ang II, and 24-h UALD were measured using the laboratory-developed LC-MS/MS. Multiple linear regression and the variance component model were applied to determine if the RI needed to be split. The RIs of PRA, PAC, and Ang II were determined using the nonparametric percentile method., Results: The laboratory-developed LC-MS/MS method was verified and showed good performance. Standard deviation ratio (SDR) sex for PAC and SDR region for Ang II are 0.466 and 0.407, respectively, indicating that the RIs of PAC and Ang II must be divided by sex and region, respectively. In addition, the SDR 24hUK for 24-h UALD is 0.579, indicating that the RI of 24-h UALD must be partitioned by urine potassium., Conclusion: RIs were established for tests related to the renin-angiotensin-aldosterone system in the apparently healthy northern Chinese Han population by the LC-MS/MS method., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background This study aimed to quantify and compare serum aldosterone (sALD) levels through three different chemiluminescence immunoassays (CLIAs) and liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. Methods Serum samples from 221 patients with suspected primary aldosteronism (PA) were retrospectively included in this study conducted at the Peking Union Medical College Hospital from June to August in 2017. sALD levels were determined using the LC-MS/MS method and three different CLIA systems, viz., DiaSorin® XL, iSYS and Auto Lumo A2000. Pooled fresh serum samples were used for recalibration. Passing-Bablok regression analysis, correlation matrix, and Bland-Altman plots were used to evaluate the concurrence among ALD levels determined using the three CLIAs. Results Within-laboratory precision of the four assays ranged from 2.1% to 9.4%, except the coefficient variation (CV) of one of the CLIAs, which exceeded 20.0% for samples with low sALD levels. sALD levels determined using LC-MS/MS were significantly lower than those determined using the other three CLIAs (p < 0.0001). Spearman's correlation coefficient of the four assays ranged from 0.745 to 0.950 (p < 0.0001). The Bland-Altman plot showed that the average bias (%) for the three CLIAs and LC-MS/MS ranged from -69.3 to -49.2. After recalibration, this correlation did not improve among the assays. However, the bias and bias percentage at the medical decision level improved between LC-MS/MS and DiaSorin® XL/iSYS. Conclusions Significant inconsistencies between the results of CLIAs and LC-MS/MS indicate that different sALD measures cannot be used interchangeably.

Aldosterone (ALD) measurement plays a critical role in screening and diagnosis of primary aldosteronism. A variety of liquid chromatography tandem mass spectrometry (LC-MS/MS) methods for serum ALD have been developed. However, the few LC-MS/MS methods for 24 h urinary ALD that have been reported require tedious sample pretreatment procedure. This study aimed to establish a novel method for quantification of ALD in urine by LC-MS/MS. Urine samples from study participants were hydrolyzed and subjected to anion exchange solid phase extraction (SPE) followed by the detection of eluates by the negative electro-spray ionization and multiple reaction monitor modes. The established method was compared with two CLIA methods and 114 participants (M:39, F:75) were recruited to study the distribution of urinary ALD in an apparently healthy population. The pretreatment time was reduced to 4 h and the total run time for each sample was 4.5 min. The linearity of the method was in the range of 2-2000 pg/mL (r > 0.999); within laboratory coefficient variation (CV) and repeatability were both <5% and recovery was within 100% ± 10%. The established method showed good consistency with two CLIA methods with the correlation coefficients of 0.993(DiaSorin) and 0.980(Auto), respectively. In the 114 apparent healthy individuals, urinary ALD was 0.74-17.09 μg/24 h (P2.5-P97.5). The method showed an excellent performance of the method, prompting us to conclude that this method may be adopted in the clinic for routine testing and analysis of ALD in urine samples., (Copyright © 2019. Published by Elsevier B.V.)

Background: This study aimed to quantify and compare serum aldosterone (sALD) levels through three different chemiluminescence immunoassays (CLIAs) and liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. Methods: Serum samples from 221 patients with suspected primary aldosteronism (PA) were retrospectively included in this study conducted at the Peking Union Medical College Hospital from June to August in 2017. sALD levels were determined using the LC-MS/MS method and three different CLIA systems, viz., DiaSorin® XL, iSYS and Auto Lumo A2000. Pooled fresh serum samples were used for recalibration. Passing-Bablok regression analysis, correlation matrix, and Bland-Altman plots were used to evaluate the concurrence among ALD levels determined using the three CLIAs. Results: Within-laboratory precision of the four assays ranged from 2.1% to 9.4%, except the coefficient variation (CV) of one of the CLIAs, which exceeded 20.0% for samples with low sALD levels. sALD levels determined using LC-MS/MS were significantly lower than those determined using the other three CLIAs (p < 0.0001). Spearman's correlation coefficient of the four assays ranged from 0.745 to 0.950 (p < 0.0001). The Bland-Altman plot showed that the average bias (%) for the three CLIAs and LC-MS/MS ranged from −69.3 to −49.2. After recalibration, this correlation did not improve among the assays. However, the bias and bias percentage at the medical decision level improved between LC-MS/MS and DiaSorin® XL/iSYS. Conclusions: Significant inconsistencies between the results of CLIAs and LC-MS/MS indicate that different sALD measures cannot be used interchangeably. [ABSTRACT FROM AUTHOR]