3.3.3. Extrapolation

It is possible to extrapolate the calculated dose-response curve beyond the measurement range of the calibration curve. Concentrations can be determined from the blank to Bmax, yielding results from zero to infinity.

Extrapolating above the highest dose of the calibration line is not recommended but is sometimes necessary if an important measurement point is just outside the dose-response curve.

Extrapolation between the blank and the lowest dose of the standard is possible in two ways. With the default setting, the calculated parameters for the sigmoid are calculated to the blank. The regression line will be sigmoid in that area.

With the "linear between blank and lowest dose" set to 1 result are calculated on a linear line between the lowest dose and the blank. This is also the case with many RIAs and ELISAs.

Results calculated in this part of measurement range are underlined in the results column of the worksheet.