The importance of preanalytics for the coagulation laboratory

Due to their complex preanalytics coagulation tests show a higher rate of rejected samples due to insufficient quality and a higher intra- and inter-individual test variability. In the last years several guidelines addressed this issue in an effort to standardize preanalytic procedures. However, in daily laboratory work, these guidelines frequently cannot be fully executed, due to technical limitations or sample transport logistics. In this manuscript several important issues in sample collection, handling and transportation will be discussed. Since the stability and variability of routine coagulation tests such as prothrombin time and partial prothrombin time are significantly influenced by a number of variables such as tube type, manufacturer, reagents used and analyzer systems, it is recommended that each laboratory develops its own manuals for sample collection, based on published data and internal evaluations.