I have some set of specific primer/probe. I've checked in on BLAST and gel electrophoresis and it was specific. However, when I run it in qPCR there are some ct value detected in negative control (not NTC). I've run this multiple times and relatively it was the same, like 1 or 2 out of three wells were detected (>approx 33ct).

I was thinking that it could be some cross-reactivity or something, but I wasn't really sure. Does anyone have any suggestions on paper that might be recommended for me to read about this? Thanks!