Until this thread I'd never been interested in Googling names. But you got me curious. <G> So I Google'd LabRat. My, the things I've done in my life!
Sadly, refining the search to Doc Klein's Labrat only brought up several Fanfic Archive references.
Personally, I just have this thing about people knowing too much about me that they don't need to know. Read government, there. So I just like to use a nick whenever I can, just on basic principle.
LabRat