The 4 Parameter Logistic (4PL) curve is the most commonly recommended curve for fitting an ELISA standard curve.
4PL regression enables the accurate measurement of an unknown sample across a wider range of concentrations than linear analysis, making it ideally suited to the analysis of biological systems like cytokine releases. This is especially true in the low-end concentrations of the standard curve, where data points would be “lost” in a linear regression.
Don’t worry, you don’t need to have a degree in Statistics to use this equation and analyze your data. Software programs like Prism or Excel allow you to run a 4PL analysis without getting into the math, and there are free online software able to run this analysis for you.