Determination of total IgE by ELISA in tubes and plates compared with PRIST.

IgE was measured by ELISA in tubes and in microtiter plates, the results being compared with PRIST data. The recommended readings of the tube contents in a spectrophotometer (SPM) were compared with results using a multi-channel photometer (MCP). Geometric mean values (International Units) and standard deviations of 44 normal sera examined by the 3 different methods were: PRIST 16.2 +/- 4.0; SPM 15.6 +/- 4.9 and MCP 18.4 +/- 4.4. Correlation coefficients were: PRIST-SPM r = 0.98; PRIST-MCP r = 0.98; and SPM-MCP r = 0.97. Intra- and inter-assay coefficients of variation were smaller for MCP than for SPM. In addition, reading in microtiter plates was much faster, while having little effect on sensitivity.