OBJECTIVE: To estimate cost-effectiveness of pathogen inactivation for platelet transfusions in Dutch cardiac surgery. We used decision-tree analysis to evaluate the cost-effectiveness of the addition of pathogen inactivation of pooled platelets to standard procedures for platelet transfusion safety (such as, donor recruitment and screening). METHODS: Data on transfusions were derived from the University Hospital Groningen (Netherlands) for 1997. Characteristics of platelet recipients (age, gender, survival) and data/assumptions on viral and bacterial risks were linked to direct and indirect costs/benefits of pathogen inactivation. Post-transfusion survival was simulated with a Markov-model. Standard methods for cost-effectiveness were used. Cost-effectiveness was expressed in net costs per life-year gained and estimated in baseline-, sensitivity- and scenario analysis. Sensitivity was analysed with respect to viral risks, discard rate and discounting. Stochastic sensitivity analysis was performed on bacterial risks. Scenario analysis was elaborated on judicial aspects and occurrence of a new yet unknown virus. RESULTS: Net costs per life-year gained were €110,000 in the baseline (90% CI: €80,000-€180,000). Sensitivity analysis revealed that cost-effectiveness was insensitive to viral risks, but highly sensitive to, for example, the assumed reduction in the discard rate and discounting of life-years gained. Sensitivity and scenario analysis showed potential reductions in cost-effectiveness down to €50,000 per life-year gained. CONCLUSIONS: Given relatively high net costs per life-year gained that are internationally accepted for blood transfusion safety interventions, our estimated cost-effectiveness figures for pathogen inactivation may reflect acceptable cost-effectiveness in this specific area. Validation of several crucial parameters is required, in particular the Dutch risk for acquiring transfusion-related sepsis. Further work should extend the model to other countries, other patient groups (haematology) and the potential elimination of donor testing if pathogen inactivation is to cover the whole spectra of pathogens and blood products.