in an RNA-seq experiment, what threshold would you use to define a set of expressed or active genes in a cell line?

Question

[rls_08]

I am trying to define a set of expressed (active) genes in my cell line for some downstream analysis. What would be your approach for defining this subset of active genes from an RNA-seq experiments? is there a minimum fpkm you would use? some standard deviation from normalized expression?

[i.sudbery]

Try: https://bioinformatics.stackexchange.com/questions/687/what-methods-are-available-to-find-a-cutoff-value-for-non-expressed-genes-in-rna/ for a start.

[ATpoint]

This has been asked many times before. Please google for 'fpkm cutoff biostars', 'expressed cutoff biostars' or similar queries. With some effort you find posts spanning the last 10 years.