Appearance of crossing point signal even in water during qPCR. Help?

03 March 2020 1 3K Report

We have been running qPCR to detect Fusarium in wheat grains. Suddenly out of nowhere, we kept getting crossing point signal in the blank (PCR water). We have done the following:

ran with only PCR mix and water --> crossing point signal appeared
ran samples with new probes, new primers, new Taq, new everything --> crossing point signal appeared
ran samples with autoclaved tips, UV-ed pipettors etc --> cp signal still appeared
ran blank capillaries --> no cp signal whatsoever

Any suggestions as to where else we could find the contamination? What else can we do to de-contaminate our things/method?

Diana Duarte-Delgado

Hi, sometime ago there was a similar question. Here is the link, you may see there my recommendations.

https://www.researchgate.net/post/How_to_get_rid_of_contamination_by_PCR_product

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