We run positive and negative control for screening cells using positive and negative antibody screening specimens which can be used as reactivity of the surgiscreen. We also run positive DAT and negative DAT specimens (Pos=rh Pos donor coated with anti-D, Neg=uncoated donor cells). We make suepension of this cells with MTS 2 plus and MTS 2 and run it on IgG gel card. this way you are testing your MTS diluents also. (Once we had negative control came up positive and it was due to contamination of MTS 2 reagent).