An enzyme-linked immunosorbent assay (ELISA) for plasma cortisol

Area of Science:

• Endocrinology
• Immunochemistry
• Biochemical assays

Background:

• Accurate measurement of plasma cortisol is crucial for diagnosing adrenal disorders.
• Traditional methods like radioimmunoassay (RIA) involve radioactive materials and specialized handling.
• Enzyme-linked immunosorbent assays (ELISA) offer a non-radioactive alternative for hormone quantification.

Purpose of the Study:

• To develop and validate a direct enzyme-linked immunosorbent assay (ELISA) for quantifying plasma cortisol levels.
• To assess the performance characteristics of the developed ELISA compared to established methods.

Main Methods:

• A direct ELISA was established using a 96-well microtitre plate.
• Cortisol-thyroglobulin conjugate was immobilized on the plate, competing with sample cortisol for antibody binding.
• Peroxidase-labeled secondary antibodies and o-phenylenediamine substrate were used for colorimetric detection.

Main Results:

• The direct ELISA demonstrated good agreement with radioimmunoassay (RIA) results.
• The assay exhibited high sensitivity, specificity, and precision.
• The method is suitable for routine use in steroid hormone analysis.

Conclusions:

• The developed direct ELISA provides a reliable and non-radioactive method for plasma cortisol determination.
• This ELISA is a viable alternative to RIA for routine clinical and research laboratories.
• The assay's performance characteristics support its application in steroid diagnostics.