Basic study of VITROS micro slide reagent with transition from JSCC recommended method to IFCC reference method for measuring lactate dehydrogenase (LD) and alkaline phosphatase (ALP) in human serum

Abstract

To support the transition from the JSCC recommended method of measuring lactate dehydrogenase (LD) and alkaline phosphatase (ALP) to IFCC reference methods, we evaluated the performance of two reagents, Vitros Slides LDHI (LDHI) and Vitros Slide ALKP (ALKP). We obtained good results in terms of repeatability and onboard stability with both reagents. LDHI and ALKP showed linearity up to 510 U/L and 837 U/L, respectively. Regarding the effects of interfering substances such as unconjugated bilirubin, conjugated bilirubin, chyle and ascorbic acid, neither reagents demonstrated any interference effects. Regarding the addition of hemolytic hemoglobin, LDHI levels increased in a concentration-dependent manner, whereas ALKP levels decreased. These IFCC reagents showed good correlation with the JSCC method, and ALKP levels were about 1/3 of reported values. Although the correlations with the IFCC standard method were confirmed, some of the samples showed discrepant results. Such results could be caused by a difference in the ratio of isozymes contained in some samples. The results of this study demonstrated that these reagents, LDHI and ALKP, are compatible with the IFCC method and have sufficient performance for clinical use, which enabled our laboratory to shift quickly to the IFCC method. Correlation studies suggest that the reactivity between these reagents and the standard IFCC wet reagents may differ by depending on the ratio of isozymes contained in samples. Therefore, it is necessary to understand the limitations and characteristics of each reagent and to provide relevant information to the clinical department if needed.