We have always use paralell testing to compare the results from one kit to the other. Recently, we started to also use the corQC serum when the kit was received and then when we needed to check the reactivity of the expired selective cells before using them. The package insert on the corQC does not mention what antibodies are in the contol. Today one of my cells from the new kit was negative with corQc serum. I am thinking maybe the CorQc dose not have an antibody to match any of the antigens in that cell. The paralell testing worked with that cell and it happened to be positive. Immucor has not returned my call. So , what do you think?