Abstract
Several reports have described that the accuracy and precision of serum calcium measurement were improved after upgrading the water purification apparatus used in the laboratory. These improvements might have been brought about owing to the supply of high-quality water. Therefore, we distributed a questionnaire on the purification system and management of water purification apparatus and the accuracy and precision of serum calcium measurement to 117 clinical laboratories in the Kanto-Koshin area of Japan. Satisfaction with the accuracy and precision of serum calcium measurement was higher in the laboratories using reverse osmosis and electro-deionization than in those using the reverse osmosis and deionization system (RO/DI). Furthermore, in the laboratories using RO/DI, dissatisfaction with serum calcium measurement was higher in those using the methyl xylenol blue (MXB) method than in those using other methods. These responses suggested that the water quality significantly affects the accuracy and precision of serum calcium measurement, and the standardization of water quality for clinical laboratories is important for the improvement of the state of the art in serum calcium measurement.
