Yes, you can.

Basically, a Custom Test is a test type that you create yourself.  Audiqueen can also come qith 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.

You can create synopsis parameters, as explained here.

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

This index now appears in the grid and in 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.

This feature is not available in the webviewer.