Mathematics and transfusion medicine.

Blood Transfus 2007; 5: 49 © SIMTI Servizi Srl This issue of Blood Transfusion contains the first article of a short series on mathematical aspects of transfusion medicine. In more than three decades of professional activity, I have noticed that there are some topics of transfusion medicine in which a mathematical treatment is important or even essential. I am not referring to theoretical questions, but to practical applications: in fact, in the course of the series, I hope the reader will appreciate that understanding the mathematical aspects is invaluable as a guide to practical decisions. With this objective in mind, I have chosen a few topics, such as the kinetics of removal in exchange transfusion and therapeutic apheresis, the factors influencing the antigen-antibody reaction in immunohaematology, the confidence limits of the leucocyte count in leucoreduced blood components. As my objective is essentially practical, I decided to give readers the possibility to perform the calculations themselves, using common computer programmes, such as Excel and the like. "La filosofia è scritta in questo grandissimo libro che continuamente ci sta aperto innanzi a gli occhi (io dico l'universo), ma non si può intendere se prima non s'impara a intender la lingua, e conoscer i caratteri, ne' quali è scritto. Egli è scritto in lingua matematica ..."