Human Chorionic Gonadotropin ELISA - HCG

Enzyme Immunoassay for the Quantitative Determination of Human Chorionic Gonadotropin (hCG) in Serum

FOR RESEARCH USE ONLY. NOT FOR USE IN DIAGNOSTIC PROCEDURES

SUMMARY
Human chorionic gonadotropin can be used as a tumor marker, as its ? subunit is secreted by some cancers including seminoma, choriocarcinoma, germ cell tumors, hydatidiform mole formation, teratoma with elements of choriocarcinoma, and islet cell tumor. For this reason a positive result in males can be a test for testicular cancer. The normal range for men is between 0-5 mIU/mL. Combined with alpha-fetoprotein, ?-HCG is an excellent tumor marker for the monitoring of germ cell tumors.

PRINCIPLE OF THE TEST
The United Immunoassay hCG ELISA Test is based on a solid phase enzyme-linked immunosorbent assays (ELISA).26, 27 The assay system utilizes one mouse monoclonal anti-hCG antibody for solid phase (microtiter wells) immobilization and another mouse monoclonal anti-hCG antibody in the antibody-enzyme (horseradish peroxidase) conjugate solution. The test specimen (serum) is added to the hCG antibody coated microtiter wells and incubated with the Zero Buffer at room temperature for 30 minutes. If hCG is present in the specimen, it will combine with the antibody on the well. The well is then washed to remove any residual test specimen, and hCG antibody labeled with horseradish peroxidase (conjugate) is added. The conjugate will bind immunologically to the hCG on the well, resulting in the hCG molecules being sandwiched between the solid phase and enzyme-linked antibodies. After incubation at room temperature for 15 minutes, the wells are washed with water to remove unbound-labeled antibodies. A solution of TMB is added and incubated at room temperature for 20 minutes, resulting in the development of a blue color. The color development is stopped with the addition of 1N HCl, and the color is changed to yellow and measured spectrophotometrically at 450 nm. The concentration of hCG is directly proportional to the color intensity of the test sample.

EXAMPLE OF STANDARD CURVE
Results of a typical standard run with optical density readings at 450 nm shown in the Y axis against Human Chorionic Gonadotropin concentrations shown in the X axis. This standard curve is for the purpose of illustration only, and should not be used to calculate unknowns. Each user should obtain his or her own data and standard curve.