we performed a combined gene expression and CiteSeq experiment with the 10x VDJ kit and 20 conjugated antibodies and sequenced on hiseq. I used cellranger to process the sequencing output. The cellranger summary shows overall good values except for a low percentage of "Antibody Reads Usable" and a low fraction of "Antibody Reads in Cells". How is it possible that so few antibody reads are usable? Does this mean that most antibodies were not bound to the cell surface?