Just compensation?

IN their recent article entitled ‘‘Improved compensation in flow cytometry by multivariable optimization,’’ Sug ar et al. (1) made the claim that introduction of double-stained controls improves the quality of the compensation process in flow cytometry. However, it seems that the conclusions presented by the authors may be well based on a logical fallacy. As demonstrated by Bagwell and Adams (2) and Roederer (3), cytometry compensation is in fact a special case of linear spectral unmixing. As such, the phenomenon known in cytometry as ‘‘spectral spillover’’ may be modeled using a basic linear spectral mixture equation. For every single measured cell