Performance Verification of Plasma Renin and Aldosterone Examination with Chemiluminescence Immunoassay and Its Screening Efficacy for Primary Aldosteronism

  Objective  To evaluate the performance of chemiluminescence immunoassay (CLIA) in examining renin and aldosterone and to determine its value for screening for primary aldosteronism (PA).

  Methods  According to the relevant documents of Clinical and Laboratory Standards Institute (CLSI), we verified the precision, linear range and carryover rate of examining renin and aldosterone with CLIA. The study included 91 suspected PA patients, using two methods, CLIA and radioimmunoassay (RIA), to examine renin and aldosterone levels in order to compare the correlation between the two methods and their value for PA screening.

  Results  The precision, linear range and carryover rate of examining renin and aldosterone with CLIA met the requirements. In patients with suspected PA, the correlation coefficients of renin, aldosterone and aldosterone-to-renin ratio (ARR) assessed by CLIA and RIA were 0.901, 0.861 and 0.847 respectively (all P<0.001). When the patients were in the upright position and the ARR was 5.636 (ng/dL)/(ng/L), the CLIA method had 79.1% sensitivity and 93.7% specificity for PA screening; when ARR was 14.084 (ng·dL^－1)/(ng·mL·h^－1), the RIA method had 93.0% sensitivity and 83.3% specificity for PA screening. When the patients were in the supine position, and the ARR was 5.640 (ng/dL)/(ng/L), the CLIA method had 97.7% sensitivity and 81.2% specificity for PA screening; when ARR was 33.494 (ng·dL^－1)/(ng·mL·h^－1), RIA had 95.3% sensitivity and 70.8% specificity for PA screening .

  Conclusion  The performance of the CLIA kit in assessing the concentration of renin and aldosterone meets the clinical requirements. Regarding preliminary PA screening, upright-position ARR had higher specificity, but lower sensitivity compared with supine-position ARR.