Comparison of an Automated Radioimmunoassay Method and a Competitive Protein-binding Method for Evaluation of Serum Cortisol
Open Access
- 1 August 1979
- journal article
- research article
- Published by Oxford University Press (OUP) in American Journal of Clinical Pathology
- Vol. 72 (2) , 146-150
- https://doi.org/10.1093/ajcp/72.2.146
Abstract
A competitive protein-binding method (CPB) for serum Cortisol determination has been compared with a newly developed automated radioimmunoassay (RIA) technic with respect to reproducibility and correlation of patient results. The RIA method uses an immobilized anti-cortisol antibody covalently coupled to the inner surface of a plastic cartridge. A mixture of 3H-labeled and unlabeled Cortisol is passed through the cartridge to achieve separation of free and bound Cortisol. The bound Cortisol is later eluted to regenerate the antibody for the next sample. The RIA procedure had a day-to-day coefficient of variation (CV) of 7% at three Cortisol levels. The CPB method had a day-to-day CV of 10% at a concentration of 8 μg/dl. A comparison of 67 patient samples showed no statistically significant difference between the methods. The regression equation was RIA = 0.96 CPB + 0.14 μg/dl, with a correlation of 0.92.Keywords
This publication has 2 references indexed in Scilit:
- An 125I-labeled cortisol radioimmunoassay in which serum binding protein are enzymatically denatured.Clinical Chemistry, 1976
- Simple Method for the Determination of Plasma CorticoidsJournal of Clinical Endocrinology & Metabolism, 1963