What is updated binning and smooth and why will it change in an upcoming FCS Express release?

Updates for Binning:

To display data on many two-dimensional plots, FCS Express divides the plot area into bins, and the number of bins used is equivalent to the plot resolution. For instance, plots displayed at 1024 resolution will divide the plot area into 1,024 bins along the X and 1,024 bins along the Y; plots displayed at 512 resolution will divide the plot area into 512 bins along the X and 512 bins along the Y axes and so on. The FCS Express team discovered that on axes using biexponential scaling, events on plots are drawn 1 bin higher than would be expected (shifted bin). For example, for events expected in bin 0, events would be drawn in bin 1; events in bin 1 would be drawn in bin 2, and so on, except for the highest bin of the plot, where events are drawn in that bin without a shift. The shift in bins has been present in FCS Express since FCS Express version 4.08. An update in FCS Express 7.30.0030 addresses the issue.

The issue was discovered when investigating the position of events located along the edges of gates created on axes with biexponential scaling during autogating development. To preserve consistency with existing work, layouts last saved in affected releases will continue to use the previous binning method, so you should not see changes related to this issue when you open the existing layouts in a newer release. Once the layout is opened in the newer release, you can choose to resave it using a new menu item and switch the binning to the newer method. If you then reopen the re-saved layout in the newer release, we anticipate that any differences observed will be minimal and not clinically relevant. The reason for this expectation is that manual gating, done by visual assessment, should remain consistent between the two releases. This issue does not affect statistical calculation, which is performed on the underlying data, independent of plot based visualizations. There may be slight differences in statistics calculated for gated populations, due to the inclusion or exclusion of a small number of events located along the edges of the gates.

 

Updates for Smoothing:

The algorithm used to smooth histogram peaks spread them only to the right instead of equally in both directions. The effect is most noticeable when using larger smoothing values, and with lower plot resolutions.

Histogram statistics and marker statistics are calculated based on the underlying data and are not affected. However, marker endpoints placed manually on smoothed histograms may reflect the visual representation of data and not fully reflect the underlying data. To see the effects, you can reduce smoothing on the plot and reposition markers if necessary. An update in FCS Express 7.30.0030 addresses the issue by ensuring histogram smoothing is symmetric.