Problems on national and locale external quality assurance schema (NEQAS and LEQAS); based on Japanese experience

The quality and stability of surveillance materials is a critical issue to perform good external quality assessment schema. In the case of nationwide surveillance, more stable materials are required than those in the case of locale external quality control schema. For locale surveillance, fresh blood, plasma or serum materials are prepared for hematology and chemistry tests. On the other hand, dried materials are used for the chemistry test and semi-fixed blood is used for hematology tests in the national surveillance. However to evaluate automated white cell differential in hematology, there has been no good materials. We therefore prepared a mixture of EDTA and ACD solution for our locale surveillance. It gave us excellent results on the differential when we used it within 3 days after blood collection.