HOW TO USE FLOW CYTOMETRY ISOTYPE CONTROLS #AskExCyte The isotype control has been historically used to help identify the non-specific background in flow cytometry experiments. There has been a lot of controversy about the use of this control in flow cytometry data interpretation. An Isotype control is an irrelevant antibody to the target, but is of the same isotype and with the same fluorochrome as the antibody in question. The Isotype control can help in identifying when blocking steps were mi