FIG. 2.

Characterization of background binding of human serum IgG in the flow cytometric bead immunoassay. In this experiment, sera from 25 persons without prior exposure to an erythropoietic agent were tested to determine the background binding to each bead. The blue, pink, and black bars represent data from three independent experiments. The assay cutoffs, described as the mean plus the standard deviations, are displayed for each assay run as corresponding, color-matched dashed lines. See the text for a detailed discussion of the data.