Electroimmunoassay of alpha1-antitrypsin with high precision

A modification of the electroimmunoassay of alpha1-antitrypsin is described. A fixed amount of the antigen is removed by addition of antibody to standards and samples before elctrophoresis. By changing the dilution procedure, the whole area of the gel plate is used for measurements within a small concentration interval. The measurement range can be changed by the addition of different amounts of antibody. The precision is increased about three fold, with a coefficient of variation within series of 0.6% to 1.2% and between series of 0.6% to 0.7%. This improvement in precision can be used to increase the significance of measured differences in alpha1-antitrypsin concentrations. The possibility of obtaining the same precision by an increased number of replicate analyses by the normal electroimmunoassay is discussed.