Hemoglobin and hematocrit are not such good candidates to detect autologous blood doping

Letter to the editor: In a recent manuscript published in the International Journal of Hematology, Sallet et al. [1] reported absolute norms of variation established for a maximal 15 days period to distinguish autologous blood transfusion from normal modifications, using hematocrit (Ht), hemoglobin ([Hb]) and stimulation index (Off-hr) (calculated using the following equation [Hb]" 60√ reticulocytes in %) as markers. The thresholds the authors proposed are 6% for Ht, 4% for [Hb] and 20% for Off-hr. Although we grant this team for setting up new parameters to fight against blood doping, the application of the indirect detecting methodology for blood doping based on maximal variation of Ht, [Hb] and Off-hr requires additional considerations. We are concerned about the method used by the authors to establish the norms to tease out the "abnormal" variation.