An Approach for Standardization of Enzyme Determinations through Quality Control Surveys

概要

論文の詳細を見る
For standardization of enzyme determinations, a great deal of efforts should be put forth from the following three standpoints; enzyme properties, clinical assessment and quality control. With regard to an approach from the third, the First International Symposium on Quality Control (ISQC, Jun. 1974, Tokyo) carried out a novel trial of enzyme surveys (LDH, Al-P), which was characterized by an experimental standpoint of view and a positive attitude to standardization, comparing with the other surveys previously conducted. At present, a more detailed analysis was applied to the data of ISQC LDH survey with permission of Dr. M. Kitamura, chairman of the survey subcommittee. In this study, a new technique to reveal systemic errors from survey data was presented and several problems to be solved in the process of standardization were described. Two steps of the statistical treatment of the data were done. The first of which was a truncation procedure, by which all the results outside ±2SD from the primary material were excluded, and a new mean and SD of the reduced material were calculated. This routine was repeated until the convergent mean and SD were obtained. Secondly, each datum was normalized against these truncated mean and truncated SD and a pair of values obtained with respect to two samples were plotted on a scattering chart. At first, regarding the survey with each laboratory method, systemic deviations essentially attributable to individual methodology were revealed by means of this technique. Several groups of method were separated according to each specificity to isoenzymes, in the scattering chart concerning two samples (2, 6) and (5), whose principal ingredients were I, II and V isoenzymes, respectively (Fig. 2). Since a projection to a new axis Z-1 gave the best discrimination, co-ordinates on this axis are considered to indicate systemic differences among several groups. Therefore, the degree of dispersion in each group on this axis seems to mean systemic errors from the reaction specificity inherent in individual methodology (systemic errors of the second sort). On the other hand, the degree of dispersion in each group on Z-2 axis rectangular to Z-1 is referred to systemic deviations that exert the same effect (plus or minus) on the determinations of two samples (systemic errors of the first sort). Youden introduced systemic (of the first sort) and random errors from a scattering chart with respect to two determinations, but systemic errors of the second sort have not been recognized and apt to be confused with random ones. We would like to emphasize that it is essential for standardization to reveal and analyze systemic errors, clearly discriminating between these two different significances of them. The projections to two axes Z-1 and Z-2 were proved to be effective to segregate two sorts of systemic errors and visualize several problems to be solved (Fig. 3, Fig. 4). Next, systemic errors revealed from the survey with uniform kit method were proved to be mainly those of the first sort (Fig. 5, Fig. 6). This fact suggested that it is an essential process for standardization to elucidate various problems in the analytical steps of enzyme determinations containing the basic set-up of the conditions, for example, temperature, reaction time and so on. 1) A new analytical technique to reveal systemic errors from survey data was presented. 2) By using this, systemic errors of the different significance from those discussed by Youden were found out (systemic errors of the second sort). 3) It is an essential process for standardization to reveal and analyze two of systemic errors, clearly discriminating each other. 4) For this purpose, it is necessary to design and execute a more elaborate survey from an experimental standpoint of view.

An Approach for Standardization of Enzyme Determinations through Quality Control Surveys

スポンサーリンク

概要

著者

関連論文

スポンサーリンク