qPCR acceptable standard deviation - (Mar/03/2015 )

Hello,

My doubt is: what is the acceptable standard deviation among my samples?

Sometimes my triplicates present a SD of 0,2 or 0,3. But sometimes this SD are 0,5 to 1,5. What value is acceptable?

Should I just eliminate one repetition to diminish my SD?

Thank you!

For unknown samples, I prefer to look at my %CV then my standard deviation. I try to keep my %CV within 10% but sometimes will accept 15-20% among my replicates if the gene expression that I am measuring is very low where you are likely to see more variation between replicates. I only exclude a replicate if two of the replicates are tight and the third is off. I rarely exclude replicates so if you are having to exclude replicates often then you should try to improve the technical reproducibility and focus on your pipetting, mixing samples, etc.