Introduction How to fit Interpolating Replicate unknowns. Inc. All Rights Reserved. Reading unknown values from a linear regression line is completely straightforward.
Prism can only read unknowns off the standard curve within the range of the standard curve.
If you enter an unknown value that is larger than the highest standard or smaller than the lowest standard, Prism will not try to determine the concentration unless you fit the standard curve with linear regression. You should interpret these extrapolations cautiously. With nonlinear regression, Prism only will perform standard curve calculations within the limits that the curve is defined. But you can extend the curve in both directions, to include lower and higher X values. Do this from the Output options dialog - press Output from the nonlinear regression parameters dialog.