Quality control and quality assessment of coagulation tests in Japan.

We have used prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (Fbg), and fibronogen/fibrin degradation products (FDP) as screening coagulation tests, and antithrombin III (AT III), plasminogen (Plg), alpha2-plasmin inhibitor (alpha2-PI), protein C (PC), thrombin-AT III complex (TAT), plasmin-alpha2-PI complex (PIC), and D-dimer as special coagulation tests. We report the present condition of internal and external quality control for these coagulation tests in Japan. We made a summary report of internal quality control of some coagulation tests in Division of Hematology Laboratory, Department of Laboratory Medicine, Hokkaido University Hospital. The repeatability and reproducibility of screening tests were good, but those of special tests were partly adequate. We have participated in some external quality control surveillance including Japan Medical Association (JMA), Japanese Association of Laboratory Medical Technologists (JALMT), College of American Pathologists (CAP), and some commercial quality control surveillance. We also reported the results of some external quality control surveillance.

Evaluation of hematological values obtained with reference automated hematology analyzers of six manufacturers.

We evaluated assays of the same fresh blood samples with six different types of reference automated hematology analyzers developed by the following manufacturers: Beckman Coulter, Sysmex, Bayer, Abbott, Nihon Kohden and Horiba. Fresh whole blood samples treated with dipotassium ethylenediaminetetraacetic acid (EDTA K2) were collected from three healthy adult volunteers. The complete blood counts (CBC) including red blood cell count (RBC), hemoglobin (Hgb), hematocrit (Hct), mean corpuscular volume (MCV), white blood cell count (WBC), platelet count (Plt), reticulocyte percentage (Ret) and leukocyte differential counts including % neutrophils (Neu), % lymphocytes (Lym) and % monocytes (Mon) were surveyed with a reference automated hematology analyzer from each manufacturer. The process from sampling to analysis was performed according to procedures in hospital clinical laboratories. RBC, Hgb, Hct and MCV exhibited allowable differences within 5% of mean value among all instruments. Large differences greater than 10% of mean value in WBC, Neu and Lym between Horiba and other manufacturers, and in Plt between Nihon Kohden and other manufacturers, were observed. Ret and Mon exhibited large differences over 10% of mean value among almost all of the instruments tested. This survey suggests that all parameters exhibiting differences greater than 10% of mean value among instruments should be improved for clinical use to ensure good external quality control in blood cell counting and leukocyte differential counting using automated instruments.