An Enzyme Linked Immunosorbent Assay (ELISA) for Detecting IgG Sensitized Erythrocytes

Abstract
An enzyme linked immunosorbent assay (ELISA) was described for detecting Ig[immunoglobulin]G sensitized [human] erythrocytes utilizing a commercially available antihuman IgG conjugated with alkaline phosphatase. Erythrocyte hemolysis in the assay was minimized by dissolving the p-nitrophenyl phosphate substrate in a carbonate-bicarbonate buffer. Nonspecific absorption of the enzyme conjugate to erythrocytes and glassware was reduced by adding 1% bovine serum albumin to wash solutions. Assay sensitivity was increased with greater concentrations of enzyme conjugate and erythrocytes in the incubation stage. Sensitivity of the described ELISA procedure was approximately equal to that of the standard antiglobulin test. Some possible future applications of ELISA in the blood bank were discussed.