Biotinylated-and Sulfo-TAG-labeled anti-IDs were used in a sandwich ECL-format to screen anti-IDs (Figure ) and six PK assay formats (Figure ). A fixed plate map was designed (Figure ) with a single biotinylated-anti-ID per plate paired with five different Sulfo-TAG-anti-IDs and a Sulfo-TAG-mouse anti-human IgG4 (Cat# 9190-01. Southern Biotech, Birmingham, AL). Similar to the indirect ECL method, condition tested included drug at 1x, 10x and 100x +/-human serum and/or +/-soluble antigen. All conditions were done in duplicate in each plate and all pipetting steps were performed with an automated TECAN system. The six PK assay formats were tested with capture and detection reagents at 0.25 µg/mL and 1.0 µg/mL concentrations respectively. Screening of five different capture anti-IDs at two concentrations across six different assay formats results in sixty 96-well assay plates or 5,760 data points.