Performance Evaluations and Costs for Internal Quality Control of the Hematology Laboratories in Regional Hospitals by Using Sigma Matrices

Abstract

This study explored the quality control (QC) data from 43 laboratories, evaluated the performance of seven hematology tests including WBC, RBC, Hb, HCT, PLT, PT, and APTT using the sigma matrix in five laboratories of regional hospitals, and calculated the cost of the internal quality control process in one laboratory of a regional hospital. In 58.1% of hematology laboratories, a single rule (mean±2SD) was used as the QC procedure for internal quality control criteria. Most of the problems were caused by a lack of knowledge and experience in interpreting the quality control results. The sigma metrics of seven hematology tests were 82.4% > 3.0. The amount of uncontrolled IQC by Westgard rules was significantly decreased compared to a single rule (p < 0.001). The expenses of IQC using a QC procedure based on actual performance assessed using the sigma matrix was 20.4% less than that using a single rule. This study concluded that most of the seven hematology tests in five laboratories had good performance with sigma > 3.0. Most laboratories used a single rule as a QC procedure without performance evaluation for clinical hematology tests. The cost of the IQC process can be reduced by approximately 20% per year by using a QC procedure based on actual performance using the sigma matrix.