Yes you can for sure have an antibody to a reagent. I have seen it a few times against 0.8% Ortho reagents in GEL. We still primarily test in tube at my reference lab but when I do go to GEL, I tend to dilute out 3% Immucor cells instead of using the Ortho 0.8% cells to avoid any issues. I know in your case Ortho cells were negative but can definitely be directed against quotient cells.