Basic study of Zn measurement using the reagent ‘Espa-Zn II’: Performance evaluation of zinc measurement reagent

Abstract

In our laboratory, zinc measurement is conducted by the atomic absorption method. As the number of specimens is increasing owing to the expanded application of zinc acetate medicine, it is necessary to consider measures to cope with this increase. Thus, we performed basic evaluation studies of the reagent ‘Espa-Zn II’ for Zn measurement by the colorimetric method using a general-purpose biochemical automatic analyzer with a high processing capacity. Results showed that with this reagent, coefficients of variation (CVs) for within-run and between-day precisions of less than 3.0% were obtained, the detection limit was 4.19 μg/dL, and the dilution linearity was also good. Although the zinc level decreased in the presence of hemolytic hemoglobin, no effect of other interfering substances was detected. In addition, comparison with the atomic absorption method showed good correlation with a regression equation of y = 1.065x + 5.8 and a correlation coefficient of r = 0.971 (n = 98). From the above results, the processing efficiency of 1,200 samples/h can be increased by using ‘Espa-Zn II’ with a general-purpose biochemical automatic analyzer, compared with the conventional processing capacity of 80 samples/h per analyzer. Although it is necessary to pay attention to hemolyzed samples, the reagent can contribute to eliminating the sample pretreatment step and a only small sample volume is required.