Signals VitroVivo: How to Add Additional Custom EC/IC Values (e.g. IC90) to a Curve Fit in Spotfire

To add a custom EC/IC value to a curve fit:

1. Open the Curve Fit configuration
   • Within the Calculation Explorer Controls panel, open the Manage Fittings tab
   • Under Select Fit, either choose an existing standard curve fit you want to modify and click the Edit button to open the configuration settings, or create a new one
2. Navigate to the Columns tab
3. Locate the Additional Points section
4. Specify the EC/IC value(s)
   • From the dropdown menu, select desired concentration type (EC/IC)
   • In the input field, enter the desired level (e.g.  90 for IC90).
   • Click the “+” button to add it as an additional output column.
5. Enable Coefficient Columns (optional)
   • Toggle Add coefficient columns to include values such as R² and any custom EC/IC points in the results table.

Additional Notes:

1. The Additional Points functionality is not available when using a Custom Fit model. These custom EC/IC column options are only available when using standard Logistic Regression models:
   • Logistic Regression - 3 parameters (3PL)
   • Logistic Regression - 4 parameters (4PL)

   • Logistic Regression - 5 parameters (5PL)

      

2. If you do not see your custom EC/IC value in your results table, you may need to add it manually to the table view: Right-click the table → Properties → Columns → select the column → Add