Graphical explanation of data analysis algorithms used in Cheburator.

<p>(<b>A</b>) Two types of IC₅₀ which can be estimated by the software. Absolute IC₅₀ is defined as the concentration of tested compound which results in 50% inhibition of cell growth as defined by assay controls (pink lines). Relative IC₅₀ is defined as the concentration of tested compound which results in half of the maximum inhibition of cell growth attainable for that particular compound (orange lines). I_max is defined as upper plateau of the dose-response curve (solid orange line). (<b>B</b>) Example of a dose-response curve drawn on the basis of 4 values (black circles). The simple two-point method uses 2 data points bracketing 50% inhibition of proliferation (green lines) to estimate the IC₅₀. In the second method, a linear model is built with the intercept and the slope, which are calculated by linear regression analysis using data points which are >0% and <100% (red lines). These parameters are later used to estimate IC₅₀. In the third method, the software uses all data points to build nonlinear regression model and estimate IC₅₀ (blue lines). Absolute IC₅₀ values are shown on this plot, but software can also estimate relative IC₅₀ in linear and nonlinear regression analysis.