Hello.

I have a problem with our in-house designed rt PCR for Cutibacterium acnes. Primers and probes were designed as part of mPCR. While testing each set of primers (monoplex) for LOD we are constantly getting false positive negative control. We repeated reaction many times. We change all reagents for new (to exclude contaminated reagents) and still the negative control in late positive in around 38 Ct. We tested negative control with 16S PCR and was negative. I was thinking to set a Cutoff/threshold? Does anybody has experiance with setting it? Thank you.

Anja