Specific enzyme immunoassay for human chorionic gonadotrophin.

Area of Science:

• Biochemistry
• Immunology
• Clinical Diagnostics

Background:

• Human chorionic gonadotrophin (hCG) is a crucial biomarker for pregnancy and certain cancers.
• Accurate and sensitive detection of hCG is vital for clinical diagnosis, particularly for trophoblastic diseases.

Purpose of the Study:

• To develop and validate a novel sandwich-type enzyme immunoassay (EIA) for human chorionic gonadotrophin (hCG).
• To assess the sensitivity, specificity, and clinical utility of the developed hCG EIA compared to radioimmunoassay (RIA).

Main Methods:

• Preparation of a sandwich-type EIA using antibody Fab'-beta-D-galactosidase conjugate and F(ab')2-immobilized silicone rubber solid phase.
• Utilized purified antibody to the beta subunit of hCG (hCG beta) for enhanced specificity.
• Evaluated cross-reactivity with human luteinizing hormone (hLH) and human follicular stimulating hormone (hFSH).
• Determined sensitivity, precision (within-run and between-run coefficients of variation), and correlation with RIA using serum samples.

Main Results:

• The EIA demonstrated high sensitivity, detecting hCG at levels as low as 0.3 mIU per assay tube.
• Exhibited minimal cross-reactivity (<4%) with hLH and hFSH, ensuring high specificity.
• Accurate determination of hCG in serum samples (6-600 mIU/ml) with precision comparable to RIA.
• Excellent correlation with RIA (r = 0.98) for 75 serum samples.

Conclusions:

• The developed sandwich-type enzyme immunoassay is a sensitive, specific, and reliable method for quantifying hCG.
• This EIA method is suitable for the clinical diagnosis of trophoblastic diseases, offering an alternative to radioimmunoassay.