Yes, you can.

A Custom Test is a test type that you create yourself.  Audiqueen also comes with a couple of built-in custom tests, such as ABR, OAE, etc.  Custom Tests typically work with software connectors such as Audiqueen Easy File Fetcher, Multimedia Capture for Win10, Audiqueen Text Editor, etc.  

Click on this support page as a good starting point for understanding Custom Test Types.

By default, each custom test type comes with a built-in index. You can enter any alphanumeric string to summerize the test result.

For more test-specific summary details, you can create synopsis parameters, as explained here.

You can assign one of these synopsis variables as an index.  For this, go to Format, then select one of the synopsis parameters and click on the 'use as index' button.

Note: assigning a synopsis parameter as an index does NOT overwrite the original built-in index.

This index now appears in the grid and the evolution graph.  For the latter, use the right-mouse button to click on the background of the graph, or check the Show Evolution Chart box in the Format window of the test type.

A synopsis parameter Volume is created to enter the tumor volume as measured on MRI.  
It is then set as Index and the checkbox 'Show Evolution Chart' is checked.

Audiqueen now shows the time evolution of the synopsis parameter 'Volume'.

The vertical axis can be inverted by double-clicking on it.

This feature is not available in the web viewer.