Human platelet survival studies have been hampered by the lack of a suitable animal model. Transfusion of human platelets into immunocompetent animals leads to the rapid destruction of these platelets by naturally occurring xenoantibodies. The non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mouse lacks T and B cells, and therefore lack natural antibodies that could destroy infused human platelets 1. Because of this property, human platelets given to the mouse intravenously circulate for several days, permitting the model to be used for testing the ability of human antibodies to cause platelet destruction in vivo 2-7. Preliminary studies have demonstrated the usefulness of the NOD/SCID mouse model for monitoring the survival and immune destruction of human platelets. However, differences exist between the research groups regarding the method of platelet injection, the amount and route of antibody injection, and the preparation of blood samples collected from the animal, making the results poorly comparable. Basically, in all laboratories, resting human platelets are injected intravenously into the mouse circulation, where they can, in the absence of platelet-reactive antibodies, circulate for up to 48 h 8. After estimatation of a baseline value (100%) of human platelets, platelet-reactive antibodies (with or without drug administration) can be infused. The impact of these antibodies on the survival of human platelets can then be analyzed by taking blood samples from the mouse over time 8. Methodological details that require attention in this model include: platelet preparation and resuspension in plasma or ‘synthetic plasma’; the concentration and volume of applied analytes (platelet, antibody, or drug); the route of platelet injection (retro-orbital injection or tail vein injection); and the route of antibody injection (intravenous or intraperitoneal). The method of data capture, including time points of blood sampling and subsequent sample preparation for analysis, the percentage of circulating human platelets, and software details, should also be reported in detail. Additional steps required to answer the scientific questions, e.g. platelet preincubation with a drug of interest or an antibody in pooled plasma or ‘synthetic plasma’, should also be reported 2, 9. Surprisingly, application procedures and the amount of injected platelets and antibodies have been only loosely defined, and standardization is necessary in order to improve the reproducibility of the procedures and to enable reliable comparison of the results. This report is not didactic in relation to how to measure the survival of human platelets with the NOD/SCID mouse model. Its purpose is to suggest standardized procedures and to define variables that should be considered when presenting methodology in published reports. The presented procedures were introduced and discussed during the meetings of the Subcommittee of Platelet Immunology of the Scientific and Standardization Committee (SSC) in Liverpool 2012 and Milwaukee 2014. Suggestions were introduced to the SSC members and the presented recommendations had unanimous agreement. Adopting these recommendations will be of advantage for investigators and laboratories to reduce imprecision and harmonize results, and will allow other laboratories to readily reproduce reported methods and findings and interpret results appropriately. Density gradient centrifugation can be used to isolate the platelet fraction (human and murine) from murine whole blood samples, e.g. with OptiPrep Density Gradient Medium (Sigma-Aldrich, Taufkirchen, Germany). Platelets are thus found in the interface layer, whereas other blood cells are pelleted. Platelet separation by density gradient centrifugation may, however, cause activation and loss of platelets, resulting in decreased recovery and a bias in the results obtained. An alternative is to fix blood samples, lyse the red blood cells, and estimate the percentage of human platelets in the platelet gate (flow cytometer). For this method, reliable commercial kits have recently been launched (e.g. the PerFix-nc Kit provided by Beckman Coulter, Brea, CA, USA). Advantages of this method include the following: no centrifugation steps are necessary, all solutions needed for the experimental procedure are ready to use as provided with the kit, the preparation time is reduced, and fixation enables measurement on the following day. It is recommended that collected samples be analyzed as soon as possible for unfixed cells, and no later than 24 h after collection for fixed cells. Analysis should be performed by two-color flow cytometry, with a mAb to identify the human platelets, and another mAb to identify the mouse platelets. The total platelet population (both mouse and human) can be gated by size and granularity. The fraction of human platelets in each sample is calculated as a ratio to mouse platelets. For calculation of survival curves, human platelets present in the baseline sample (30 min after injection) are considered to represent 100%. For many medications, the metabolism in the mouse is quite similar to that in humans. The model can therefore be used to identify metabolite-specific antibodies that are capable of causing thrombocytopenia in patients sensitive to certain medications 6. Drugs are injected intraperitoneally at doses sufficient to maximize the interaction with target cells and drug-dependent antibodies without becoming toxic to the animals. The sensitivity for antibody detection can be increased by injecting drugs/the drug at suprapharmacologic (but subtoxic) concentrations 6. The time of blood sampling should be based on the rate of formation of the drug metabolites or, if the literature information is insufficient to determine this, on the half-life of the parent drug. In order to maximize the antibody interaction with human platelets, it is recommended that purified (Melon Gel; Pierce, Rockford, IL, USA) IgG be injected intravenously or, in the case of drug-dependent antibodies, that human platelets be suspended in the patient sample containing the drug-dependent antibodies prior to injection. IgG fractions should be freshly isolated (not stored at 4 °C), to avoid the formation of IgG aggregates. The concentration of human IgG should be adjusted consistently in the test samples and in the negative control to a final concentration of 5–10 mg mL−1. In studies that are proposed to assess the ability of platelet-reactive antibodies to activate platelets, the activation status of human platelets should be assessed prior to the injection by analyzing the expression of P-selectin (after incubation with buffer and thrombin receptor-activating peptide-6). These samples can be fixed, and later measured together with the samples obtained to study human platelet survival. Although recent reports have proved the usefulness of the NOD/SCID mouse model for studying the role of human platelet antigen-1a antibodies in the clearance of antigen-positive platelets in cases of post-transfusion purpura and neonatal alloimmune thrombocytopenia, and the role of drug-dependent antibodies specific for drugs and drug metabolites in drug-induced immune thrombocytopenia and autoimmune thrombocytopenia, other possible uses could be envisioned. These include studies of platelet storage conditions, assessment of platelet therapeutics, and studies of platelet destruction in heparin-induced thrombocytopenia, thrombotic thrombocytopenic purpura, or hemolytic–uremic syndrome. However, one of the major limitations of this model is the difficulty in studying the function of human platelets, owing to the overwhelming number of mouse platelets in the system. Therefore, this model is recommended for the study of human platelet survival, but not for the assessment of human platelet function. T. Bakchoul designed the study, analyzed the data, critically wrote the manuscript, and revised the intellectual content of the manuscript. J. Fuhrmann analyzed the data and critically wrote the manuscript. B. H. Chong designed the study and critically wrote the manuscript. D. Bougie designed the study, analyzed the data, and critically wrote the manuscript. R. Aster designed the study, critically wrote the manuscript, and revised the intellectual content of the manuscript. All authors approved the version to be published. This study was supported by a grant from the German Society for Research (Deutsche Forschungsgemeinschaft DFG) to T. Bakchoul (BA-5158/1-1). The authors thank A. Greinacher for his support and helpful discussion. D. Bougie and R. Aster report receiving grants from National Heart, Lung and Blood Institute during the conduct of the study. The other authors state that they have no conflict of interest.