CH-eGFP-WS-derived lentiviral vectors were produced in separate productions indicated by a production number. RNA and p24 concentrations were determined in the same assays to reduce inter-assay variation. Before transduction of 293T cells, vectors were normalized for RNA or p24 concentration. Two days later, cells were harvested to determine the percentage of transduced cells by FACS (TE or transduction efficiency). TE values relative to the first production are presented as well. A high variation was observed after normalization for either RNA or p24.