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.
- A serological assay of tetanus sera - Four-parameter logistic curve analysis.Reference: European Pharmacopoeia, Chapter 5.3, 5.4.1.