Electroimmunoassay of Alpha₁-Antitrypsin with High Precision

Abstract

A modification of the electroimmunoassay of α₁-antitrypsin is described. A fixed amount of the antigen is removed by addition of antibody to standards and samples before electrophoresis. 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 threefold, 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 α₁-antitrypsin concentrations. The possibility of obtaining the same precision by an increased number of replicate analyses by the normal electroimmunoassay is discussed.

Key Words:

• Coefficient of variation
• pre-precipitation