Aldosterone determination: comparison of a RIA assay and a CLIA assay.

Clinical biochemistry (2014-12-03)
Nassima Belaidi, Agnès Georges, Julie Brossaud, Jean-Benoît Corcuff
ABSTRACT

To extend knowledge about the clinical performances of a new chemiluminescent immunoassay (CLIA) for aldosterone set up in available analysers. We compared the results of a RIA assay to those of a CLIA assay in 198 serum and 80 urine samples from patients in endocrine and hypertension departments. Furthermore, for serum samples the concordance of results for postural tests was analysed. RIA and CLIA aldosterone serum concentration was linearly correlated with a slope of 0.988 and an intercept of 70.4pmol/L. The variations of aldosterone serum concentration obtained with the two assays during postural tests were very consistent. There was no significant difference of aldosterone concentrations after thawing with the CLIA assay. RIA and CLIA aldosterone urine concentrations were linearly correlated with a slope of 0.787 and an intercept of -2.64nmol/L. Omitting the preservative boric acid from urine samples did not modify aldosterone concentration at least up to 48h after collection. The RIA and CLIA assays were well correlated for the most useful serum samples. It is well suited to circumvent isotopic assays with the throughput of available analysers.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Hydrocortisone, BioReagent, suitable for cell culture
Sigma-Aldrich
Hydrocortisone, ≥98% (HPLC)
Sigma-Aldrich
Hydrocortisone, γ-irradiated, powder, BioXtra, suitable for cell culture
Supelco
Hydrocortisone, Pharmaceutical Secondary Standard; Certified Reference Material
USP
Hydrocortisone, United States Pharmacopeia (USP) Reference Standard
Sigma-Aldrich
Hydrocortisone, meets USP testing specifications
Hydrocortisone for peak identification, European Pharmacopoeia (EP) Reference Standard
Hydrocortisone, European Pharmacopoeia (EP) Reference Standard
Hydrocortisone, British Pharmacopoeia (BP) Assay Standard
Supelco
Hydrocortisone, VETRANAL®, analytical standard