Matched antibody pairs are monoclonal and a polyclonal antibodies selected to work together in sandwich ELISA. Conventional wisdom suggests that a polyclonal antibody is often more sensitive, driving the sensitivity of the assay.
This approach may be acceptable for one-off experiments. However, batch-to-batch variability of polyclonal antibodies make this experiment difficult to repeat. Recombinant monoclonal antibodies have far less batch-to-batch variability increasing the reproducibility.
Figure 1 shows a conventional ELISA (made with monoclonal and polyclonal antibodies) developed to quantify fibrinogen, the cardiac infarction biomarker, has poor batch-to-batch consistency. When this ELISA was made with monoclonal capture and detector antibodies, the required reproducibility and batch-to-batch consistency were achieved.
Figure 1. Lot-to-Lot comparison of human fibrinogen antibody pair performance. Background-subtracted data values (mean +/- standard deviation) are graphed. Click on the image to enlarge.