Luminex MasterPlex QT Tutorial Manual - Manual (Page 15)

http://www.miraibio.com 15 Master Plex QT
We’ll mark A1 as background: Highlight the well, then right-click, and from the menu,
select Mark Wells → Absolute Quantification → Background.
The well will change color to copper (you may have to click on another well to change
the highlighting to see the copper color indicating a background well).