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Determining low product cut off using Ct - How to decide Ct level at which expression is unreliable (Mar/25/2007 )


I am using SYBR green for relative quanification, and analysing my first real-time data.
The expression levels of my target gene are quite low or no expression in some tissues that I am looking at.

I was wondering if anyone knew of a method (justified and preferably published) for creating a cut off point for when your Ct value gets beyond 37 and when some replicates (in a triplicate) are undetectable.

Hope this makes sense. I can try to explain further if needed.




I actually have the same question. One replicate in a triplicate often often has Ct value of "N/A". How does one quantify that in calculations?