Human Immunoglobulin G (IgG) is the most abundant immunoglobulin in serum and is predominately involved in the secondary immune response. The IgG subclasses are designated 1, 2, 3 and 4 based on their relative prevalence in human serum. The sensitive quantitative measurement of total human IgG antigen in serum, plasma, hybridoma cell supernatants, ascites or other biological fluid samples is easily performed with this 96 well strip format ELISA kit. The assay does not distinguish IgG subclasses. The concentration of IgG in normal human serum ranges from 5 to 12 mg/ml. The assay measures human IgG in the 0.2-200 ng/ml range. Samples giving human IgG levels above 200 ng/ml should be diluted in blocking buffer before use. A 1:1,000,000 dilution for plasma and serum is suggested for best results. Human IgG will bind to the capture antibody coated on the microtiter plate. After appropriate washing steps, biotin labeled anti-human IgG primary antibody binds to the captured protein. Excess primary antibody is washed away and bound antibody is reacted with peroxidase conjugated streptavidin. Following an additional washing step, TMB substrate is used for color development at 450nm. Color development is proportional to the concentration of human IgG in the samples. A standard calibration curve is prepared in blocking buffer using dilutions of purified human IgG and is measured along with the test samples. All reagents and standards are provided in these ELISA kits.

The human IgG standard provided in this kit is calibrated against the WHO International Standard for Human Serum Immunoglobulins G, A and M (NIBSC Code 67/086).