Why Is Elisa Curve Sigmoidal?

Semi-log plot helps counteracting the compression at the lower end caused by linear plots. Semi-log plots use the log of the concentration against the readout. This method commonly results in a sigmoidal curve that distributes more evenly the data points.

Should ELISA standard curve be linear?

We recommend including a standard on each ELISA plate to provide a standard curve for each plate used. ... The concentration of the positive control sample should be within the linear section of the standard curve in order to obtain valid and accurate results.

Why do standard curves plateau?

Typically, a standard curve will have a sigmoidal shape in which the higher concentrations of standard dilutions will reach a plateau in absorbance. ... If a diluted sample is used, remembered to multiply by the dilution factor to obtain the final value.