Enzyme immunoassay for cortisol in serum using cortisol 21-amine

Area of Science:

• Clinical Chemistry
• Biochemistry
• Immunoassay Development

Background:

• Accurate measurement of serum cortisol is crucial for diagnosing adrenal disorders.
• Existing methods like radioimmunoassay may involve radioactive materials, necessitating alternative approaches.
• Cortisol 21-amine is a novel derivative for immunoassay development.

Purpose of the Study:

• To prepare cortisol 21-amine and develop a novel enzyme immunoassay (EIA) for serum cortisol determination.
• To evaluate the performance characteristics of the developed EIA.
• To assess the utility of cortisol 21-amine as a cortisol-enzyme conjugate.

Main Methods:

• Synthesis of cortisol 21-amine.
• Conjugation of cortisol 21-amine with alkaline phosphatase.
• Establishment and validation of the enzyme immunoassay using serum samples.
• Comparison of EIA results with radioimmunoassay (RIA) values.

Main Results:

• The enzyme immunoassay detected a minimal amount of 1 ng/tube of cortisol.
• The measurable range for serum cortisol was 1 to 80 µg/dL using a 10 µL serum sample.
• The EIA demonstrated excellent dilution, accuracy, and precision, meeting standard criteria.
• Serum cortisol values obtained by EIA correlated well with those from radioimmunoassay.

Conclusions:

• Cortisol 21-amine is a valuable derivative for creating cortisol-enzyme conjugates for enzyme immunoassays.
• The developed enzyme immunoassay is accurate, precise, and suitable for routine serum cortisol determination in clinical laboratories.
• This EIA offers a non-radioactive alternative for quantifying serum cortisol levels.