There are many benefits to the overall process of standardization for tests of hemostasis and thrombosis. Nevertheless, it should also be recognized there are several specific problems and limitations to this process, as highlighted in this review. Some of the issues are formidable, but it is hoped that they are not insurmountable. Sometimes, clinical pressures drive diagnostic test processes before they are formally proven to be of clinical value. Such clinical pressures drive diagnostic changes in the hemostasis laboratory, including the incorporation of new and emerging technologies, which in turn drives the need for evolving and effective external quality assurance. Incorporated into the diagnostic or test-performance process are a large number of organizations involved in driving standardization, with the ultimate intention of improving diagnostics, but this process will also have unintended potential for adverse outcomes. Although this review notes many of the benefits to the process, it focuses primarily on those negative factors that are often less obvious but still require attention and process review.