1. Collection, transport and processing of blood specimens for coagulation testing and general performance of coagulation assays. Approved guideline H21-A2,1998
2. stability and precision using buffered sodium citrate;Simmons;Lab Med,1993
3. The effect of blood sample storage and transport on the PT in anticoagulated patients;Fiore;Thromb Haemost,1993
4. Prothrombin time determination. The lack of need for a discard tube and 24-h stability;Brigden;Am J Clin Pathol,1997
5. Pre-instrumental variables in coagulation testing;Koepke;Am J Clin Pathol,1975