The purpose of this study was to evaluate the influences of delayed sample analysis on the stability of erythrocyte parameters and reticulocyte parameters for antidoping tests performed on the ADVIA120 system. We analyzed erythrocyte count, hemoglobin, hematocrit, mean cell volume, percentage of hypochromic erythrocytes, percentage of macrocytes, absolute reticulocyte count, percentage of reticulocytes, mean cell volume of reticulocytes, cell hemoglobin of reticulocytes, percentage of high-fluorescent reticulocytes, and OFF-Score during a 48-hour storage period at 4 degrees C or 21 degrees C. Data analysis was performed by fitting linear or nonlinear mixed-effects models. We then modeled appropriate trends and tested the curve parameters' interaction with the ambient temperature. We observed that chilling of samples to 4 degrees C generally proved more advantageous than storage at room temperature. Sufficient stability during 48-hour intervals was demonstrated for erythrocyte count, hemoglobin, percentage of reticulocytes, absolute reticulocyte count, cell hemoglobin of reticulocytes, percentage of hypochromic erythrocytes, percentage of high-fluorescent reticulocytes, and OFF-Score. We concluded that for the establishment of individual blood profiles the corresponding samples should be transported and stored at 4 degrees C. Analysis should be performed not later than 48 hours after sampling.