Method Description

The BioPlex 2200 cytomegalovirus (CMV) IgG assay uses multiplex flow immunoassay technology. Briefly, CMV antigen-coated fluorescent beads are mixed with an aliquot of patient sample and sample diluent and incubated at 37° C. During this time IgG anti-CMV antibodies in the specimen will bind to the CMV antigen on the beads. After a wash cycle, a fluorescently labeled antihuman IgG-antibody conjugate is added to the mixture and incubated at 37° C. Following a wash step to remove unbound conjugate, the bead mixture is passed through a detector that identifies the bead based on dye fluorescence and determines the amount of antibody captured by the antigen based on fluorescence of the antihuman IgG conjugate. Raw data are calculated in relative fluorescence intensity and is converted to an antibody index for interpretation. Antibody index (AI) values 0.8 and lower are considered negative. AI values of 0.9 and 1.0 are equivocal. AI values 1.1 and above are considered positive. Three additional dyed beads, an internal standard bead, a serum verification bead, and a reagent black bead are present in each reaction mixture to verify detector response, the addition of serum to the reaction vessel and the absence of significant nonspecific binding in serum, respectively.(Package insert: BioPlex 2200 System, ToRC IgG, Bio-Rad Laboratories;03/2012)