BACKGROUND: Lack of generalized guidelines for DNA @entity450 ( @entity450 ) may be the main reason for its limited use in the clinical management of @entity0 . METHODS: After an initial interlaboratory reproducibility study (Round I), we concluded that it was the evaluation of the DNA histograms rather than the technical performance of the analysis that was the main reason for discordant results between laboratories. Guidelines for the interpretation of DNA histograms were therefore drawn up. We present here data from a new reproducibility study (Round II) using these guidelines. RESULTS: For 10 laboratories also participating in Round I, use of the guidelines increased the concordance in DNA ploidy status from 89% to 100% for the 46 samples used in both rounds. The concordance rate for SPF also increased; mean r(s)-value increased from 0.81 to 0.88, and mean kappa value (lower two-thirds versus upper third versus not reported) increased from 0.55 to 0.71. Five new laboratories, participating only in Round II, also agreed with the 10 original laboratories regarding DNA ploidy status. With the inclusion of all 15 laboratories, we obtained a mean r(s)-value of 0.81 and a mean kappa value of 0.72 for SPF. CONCLUSIONS: Generalized guidelines for DNA @entity450 increase interlaboratory agreement, which is highly important in clinical routines and in multicenter studies. Furthermore, inexperienced @entity450 laboratories using generalized guidelines can produce and interpret DNA @entity450 data equally as well as experienced laboratories.

Improved DNA flow cytometric, DNA ploidy, and S-phase reproducibility between 15 laboratories in analysis of XXXX using generalized guidelines.

@entity0 :: ('MESH:D001943', 'Disease') :: ['breast cancer'] @entity450 :: ('MESH:D006940', 'Disease') :: ['flow cytometric analysis', 'FCM']
@entity0 :: (MESH:D001943,Disease) :: ['breast cancer']
