RÉSUMÉ
BACKGROUND: Among the results of an unexpected antibody screening test using IH-1000, ‘undeterminable’ results can be obtained. Repeated tests not only use reagents and consumables but also cause a turnaround time delay. Therefore, it is important to reduce the ‘undeterminable’ results and to determine the effects. METHODS: From January to early June, 2016, 2,872 cases/259,455 tests (1.11%) of ‘undeterminable’ were detected in the screening test. The factors considered to affect the ‘undeterminable’ were classified into four categories: ① reagent, ② consumables, ③ inspection environment & specimen, and ④ enhancing the equipment management. For data comparison, a chi-square test was conducted (95% confidence interval, 0.05 significant level). RESULTS: The incidence of ‘undeterminable’ cases decreased from 1.11% before management to 0.66% (P < 0.001) after Pool Cells management. The consumption of ‘LISS/Coombs Card’ decreased from 1.07% before management to 0.51% (P < 0.001) after management. By maintaining a clean inspection environment and strengthening sample management, the rate decreased from 1.11% before management to 0.66% (P < 0.001) after management. On the other hand, there was no difference in the incidence of ‘undeterminable’ between before and after IH-1000 management reinforcement. CONCLUSION: Among the factors predicted to affect the decrease in the incidence of ‘undeterminable’, the management of Pool Cells and keeping the inspection environment clean as well as improving sample management contributed the most to the reduced ‘undeterminable’. Improvements in the management of consumables, and removing dust from the inside of the equipment, had a positive impact. A continuous quality improvement theme has been adopted and it is helpful for managing and improving the predicted factors.