Nonlinear quantitative response assay

parallel-curve model, full curve fits

A nonlinear quantitative response assay is a full curve fit method which takes the whole dose-response relationship into consideration, including asymptotes.

When you do a biostatistical analysis with our PLA 3.0 bioassay software, you can chose between different types of nonlinear full curve fits:

  • 4-parameter logistic curve fit
  • 5-parameter logistic curve fit
  • 3-parameter logistic curve fit

The 4-parameter logistic curve fit is the most common approach. It models a symmetric sigmoidal dose-response correlationship. The 5-parameter logistic fit function adds an asymmetry parameter. The 3-parameter models is a reduced 4-parameter model, where one of the asymptotes has to be set to a fixed value or to the mean of a control line, which allows the system to deal with truncated data.

PLA 3.0 allows you to carry out the regression for each standard/sample combination in your bioassay separately or at once.