QUALITY-CONTROL STUDY BY THE FRENCH CYTOMETRY ASSOCIATION ON FLOW CYTOMETRIC DNA CONTENT AND S-PHASE FRACTION (S-PERCENT)

Clinical use of flow cytometric (FCM) DNA analysis requires effective quality controls, Thirty-two laboratories with various degrees of FCM experience participated in the first phase of a quality control progra m organized by the Association Francaise de Cytometrie. All received d iskettes containing ten list-mode files and ten histogram files that w ere derived from FCM analysis of various unfixed tumor specimens, A to tal of 610 responses on DNA ploidy and cell cycle were obtained with t hree different DNA analysis softwares: CellFit used by (44% of respons es), MultiCycle (44%), and ModFit (12%), After statistical analysis, 3 1% of the responses were excluded from the final analysis for precise reasons, The groups were too small to carry out a valid analysis of th e slight differences in the percentage of cells in the DNA synthesis p hase (S%) between CellFit and MultiCycle. To estimate the influence of gating on the final cell-cycle results, five of the histogram files w ere derived from corresponding list-mode files, but the participating laboratories were unaware of this, A good correlation (r = 0.98) was o btained for S% values in the five paired files, The fact that 31% of t he responses had to be excluded clearly reflects inadequate training i n the use of these analysis softwares and, in some cases, a failure to grasp the biological meaning of the results, in contrast, the laborat ories fulfilling consensus recommendations obtained remarkably homogen eous results, showing that standardization is feasible. (C) 1996 Wiley -Liss, Inc.