REPRODUCIBILITY OF DNA-PLOIDY AND S-PHASE VALUES FROM PARAFFIN-EMBEDDED TISSUE

OBJECTIVE: To determine the degree of variability of DNA flow cytometr ic results between two types of flow cytometers. STUDY DESIGN: Single- cell suspensions were made from 40 paraffin blocks of ovarian carcinom a using a modified Hedley procedure. These samples were consecutively analyzed in both Coulter's Profile II and Elite Flow cytometers. Gated and ungated data were collected and analyzed using Phoenix flow syste m's multicycle software. RESULTS: There were 16 (40%) DNA diploid, 23 (58%) DNA aneuploid and 1 DNA tetraploid tumor. The degree of variabil ity in the DNA index coefficient of variation of the G0/G1 diploid pea k, percentage of S phase, percentage of G2M, percentage of debris plus percentage of clumps were compared. Excellent correlations of the res ults were obtained in the DNA index (r=.999) and in percentage of S ph ase (r=.946). CONCLUSION: It is feasible to standardize variables of f low cytometric instruments to obtain reproducible results.