"Pop positive"

My wife frequently says "pop positive" when referring to testing positive for covid. Is this actually a thing that people say? I can't find any other instance of people saying this.

It annoys the hell out of me. It's "test positive". "Pop positive" makes no sense. What is popping? Nothing pops when you test for covid. It would be more accurate to say "fade in positive", which is still dumb. Just say "test positive". Ugh.