Sources of experimental variation in calibration curves for enzyme-linked immunosorbent assay

Enzyme-linked immunosorbent assays are usually performed by running standard and unknown concentrations together on the same microtiter plate, because the standard curve is known to vary considerably from one assay to the next. Here we examine experimentally the sources and nature of this variation, and discuss the possibility of reducing the cost of the assay by using a batch of plates, only one of which is used to generate the calibration curve. We present a method for doing this, and test it empirically.