Measurement of nanogram concentrations of IgG by mixed hemadsorption

We have modified the mixed hemadsorption technique so as to minimize the non-specific adsorption of indicator cells. This is accomplished by: (1) introducing fetal calf serum at several crucial steps in the procedure, and (2) standardizing the selection of high-power fields to be counted so as to avoid erratic adherence patterns which occur around the well rim. Using these adjustments, IgG concentrations in the 12.5--400 ng/ml range can be measured accurately.

2 microliter. Test time: 4 h. No radioisotope is required.