Sandwich enzyme immunoassay of human chorionic gonadotropin using polystyrene beads as solid support

Area of Science:

• Immunology
• Biochemistry
• Assay Development

Background:

• Human chorionic gonadotropin (hCG) is a crucial biomarker for pregnancy.
• Accurate and sensitive detection of hCG is essential for early pregnancy diagnosis.
• Existing methods like radioimmunoassay (RIA) have limitations.

Purpose of the Study:

• To develop and validate a solid-phase sandwich enzyme immunoassay for human chorionic gonadotropin (hCG).
• To utilize monoclonal antibodies targeting beta- and alpha-subunits of hCG for enhanced specificity and sensitivity.
• To compare the performance of a one-step and a two-step assay procedure.

Main Methods:

• Solid-phase sandwich enzyme immunoassay utilizing polystyrene beads as solid support.
• Coating beads with monoclonal anti-beta-hCG antibody.
• Labeling monoclonal anti-alpha-hCG antibody with horseradish peroxidase.
• Performing the assay via "one-step" or "two-step" procedures.
• Validation using urine samples from pregnant women and comparison with radioimmunoassay.

Main Results:

• The two-step procedure demonstrated a sensitivity of 7.8 ng hCG/ml and a linear range up to 500 ng hCG/ml.
• The one-step procedure had a measurement range between 15.6 and 125 ng hCG/ml.
• Both procedures showed high accuracy, with a correlation coefficient of 0.987.
• Analysis of 21 urine samples showed comparable results to radioimmunoassay (r = 0.956).

Conclusions:

• The developed enzyme immunoassay is a sensitive and accurate method for quantifying hCG.
• The assay shows high correlation with radioimmunoassay, making it a viable alternative.
• The use of monoclonal antibodies enhances the specificity and reliability of hCG detection.