All assays have been tested and designed to give accurate and reproducible results over the range of standards shown in the insert. Additional points higher or lower than those may not improve assay performance. Changed standard concentrations could cause inaccuracies by not giving adequate data at important assay points. Remember also that assays have a limit of sensitivity that is a function of the antibodies and buffers used in the test. Simply adding additional standard concentrations to the lower end of the curve will not make the test more sensitive. Following the standard curve dilution recommendations will generally give you the best results.
