[Current problems in quality control (QC) in hematology]. 
Total quality control (TQC) is one of the most important issues in laboratory hematology.  As for complete blood count (CBC), almost all blood cell counters possesses quality control (QC) programs for its determination, and values of high quality can be provided by the counters.  Reticulocytes can be determined precisely as well.  However, mean cell volume (MCV) were slightly different among blood cell counters when semifixed QC materials were used for its surveillance.  No QC materials to evaluate white cell differential functions have not be found for the common use now.  Thus, urgent matter would be the development of appropriate QC materials to be used for overall blood cell counters.  In coagulation testings, trials for common use of international normalized ratio (INR) for the prothrombin time (PT) test has been continued yearly due to the varieties of biophysical characteristics among PT reagents.  Similar variation are also present among activated partial thromboplastin time (APTT) reagents.  Some improvement would be required.