Try using the pattern argument: fsc <- "FSC-A" ssc <- "SSC-A" comp.mat <- spillover(x=compSet,unstained=compNames[1], patt="FITC-A|PE-A|APC-A|APC-Cy7-A|FSC-A|SSC-A", fsc=fsc,ssc=ssc,method="median") Perry Haaland, Ph.D. BD Fellow, Bioinformatics BD Technologies (919)-349-2172 perry_haaland at bd.com ----------------------------------------- ******************************************************************* IMPORTANT MESSAGE FOR RECIPIENTS IN THE U.S.A.: This message may constitute an advertisement of a BD group's products or services or a solicitation of interest in them. If this is such a message and you would like to opt out of receiving future advertisements or solicitations from this BD group, please forward this e-mail to optoutbygroup at bd.com. ******************************************************************* This message (which includes any attachments) is intended only for the designated recipient(s). It may contain confidential or proprietary information and may be subject to the attorney-client privilege or other confidentiality protections. If you are not a designated recipient, you may not review, use, copy or distribute this message. If you received this in error, please notify the sender by reply e-mail and delete this message. Thank you. ******************************************************************* Corporate Headquarters Mailing Address: BD (Becton, Dickinson and Company) 1 Becton Drive Franklin Lakes, NJ 07417 U.S.A.