Quality control rules used in external quality assessment of quantitative assay in clinical laboratories

External quality assessments play important roles in quality improvement in clinical laboratories, but most laboratories focused on the unsatisfied data only. With appropriate quality controls, laboratories can detect not only the error sourses of unsatisfied data but the potential error sourse of satisfied data as well.(Chin J Lab Med, 2015, 38: 357-358) Key words: Quality control; Quality assurance, health care; Bias(Epidemiology)