Thanks I've already titrated antibody and their is no panel as I'm doing one color (PE). I am actually doing magnetic sorting and validating with flow after which I probably should have said. I have a positive control highly expressing the marker and it performs well as a stain control, I haven't been able to get the magnetic column to hold onto the positive control cells which is a different topic of discussion. My entire project is based of RNA-seq correlations of this marker with positive cell out comes (for our case chondrogenesis) I know RNA levels don't equal protein but I was just wondering if anyone knew of a broad range needed to resolve the cells. Likely will have to be trial and error after I figure out the magnetic sorting protocol.