Copy to/from Prism Graph

Most instruments that measure ELISA assays allow you to fit data to a standard curve before exporting it. However, if you only have raw absorbance data that requires fitting to a standard curve then the “Copy to/From Prism Graph” function is useful to help you export the data to a curve fitting program such as Prism graph. The way to use this program is as follows. Select the data from the original microtitre plate that you want to export to Prism Graph.

And select “Copy To/From Prism Graph”. The following dialogue box will be displayed.

**Figure 1:** The Prism Copy/Paste Dialogue box.

At this point, the program will take the data selected in Excel and copy it to the clipboard converting it to a single column of numbers. For example, if you selected the following 2D matrix of numbers above, they will be converted into a single column of numbers by stepping through the numbers column by column as shown in Figure 2A.

This single column format is compatible with the Prism Graph Curve fit feature (Figure 2). Using Prism Graph or a similar type of program one can now highlight the new fitted value (Figure 2C) and copy these values back to the clipboard.

**Figure 2:** The “Copy To/From Prism Graph” function in the Platemaker Wizard. Prism Graph supports curve fitting and the first step is to create a standard curve using Prism curve fit algorithms and the data from your plate(s) that specify your standard curve or curves (*panel A*). Next select the area of your plate that contains the absorbance values of all your test samples and then select the “Copy To/From Prism Graph” option in the Platemaker Wizard menu. Your 2D plate data will be converted into a single column inside the Windows clipboard so that when you switch over to Prism Graph and paste the data under the standard curve absorbance values, it will all appear in the first Y column on the Prism graph data sheet (*panel B*). The user can then switch over to the Prism Graph Interpolated X values page (for more information, see the Prism Graph help menu) where the sample absorbance values have been converted to standard curve sample values using the fitted curve from your plate standards (*panel C*). Select these values and copy them back to the clipboard. If you now switch back to Excel, you can paste these values back into your original selected plate area by simply pushing the OK button on the dialogue box to place them back into their original layout within the selected block area.

When you switch back to Excel you now can press OK on the dialogue box (Figure 1) and the following message will be displayed:

**Figure 3:** The Prism Copy/Paste Dialogue box after pushing OK for the first time.

This second message is to make sure you have the transformed data copied into the clipboard from Prism Graph. Now simply push OK and your original selected numbers will be replaced by the newly calculated number from Prism where conversion was possible:

Copy to/from Prism Graph

Platemaker Wizard Utilities