Various approaches to standardization and the importance of measurement accuracy

Biochemical measurements of quantities, i.e. analytes, of the haemostatic system are the basis of evaluating patients with potentially serious or lifethreatening disorders. Therefore, there is a need of a high level of certainty of the results. Experience based on the comprehensive international standardization of prothrombin time measurements (recommended nomenclature: coagulation, tissue factor induced, time) proves that a high level of certainty can be reached and that standardization of methods (reference methods, field methods) as well as availability of international reference materials are elements of main importance. Yet, for most quantities within haemostasis such an official standardization system does not exist. This article emphasizes that the use of reference materials alone does not secure accuracy and that a high level of measurement accuracy is a main element in standardization. It is advocated that further progress of standardization within haemostasis is dependent on definition of methods with evidence based accuracy and the development of provisional reference methods and on the availability if international reference materials for specific analytes.