Four Parameter Logistic Curve

  • Email link to this assay page
Play Video Guide
(4 min 31 sec)
4PL

Quantitative analysis of samples using a Four Parameter Logistic (4PL) curve fit suitable for calculating concentrations from symmetrical sigmoidal calibrators. This method is widely used and cited in data analysis for typical ELISAs.

This analysis optionally includes a background correction step. If a blank group is included on your layout, the mean of the blank replicates is first subtracted from the raw data measurements (the corrected values are then used in the fit).

The standard data points (concentration vs. measurement) are plotted on semi-log axes and a 4PL is made through the points. The concentrations of the samples are determined from the fit with any specified dilution factors applied.

Note, the concentration units are unspecified; use whichever units are applicable for your standards (the calculated concentrations will use these same unspecified units).

The %CV, Standard Deviation and Standard Error are calculated for each replicated sample.

Samples outside the range of the standards or the fit (greater than the upper asymptote or below the lower asymptote) are highlighted in yellow.

See also Related assays
1

Measurements

Supply your measurement data: Help
Help You can supply your raw data in two ways:
  1. Enter (or Paste) the raw data into the edit box. Use the same format as the example data (i.e. numbers separated by spaces). More...
  2. Select a data file on your computer and press Upload. Most raw data file formats are automatically recognised and processed. Formats not currently supported can be added very quickly. More...
After reviewing other analysis parameters press the Calculate button below to process your results.
 
Help
Help Select option to provide and process measurement data read across multiple plates. More...
2

Microplate

3

Standard Concentrations

4

Dilution Factors

5

Sample IDs

6

Run Notes