血清電解質 (Na, K, Cl) の統一化の試み

A trial in standardizing the measured values of serum electrolytes (Na, K, Cl) was carried out in 22 clinical laboratories in Gunma prefecture. First, precision was evaluated, then confirmation of maintenance of precision and quantative analysis of factors changing determination were performed, and finally, accuracy of electolyte measurement was evaluated.<BR>Twenty-one laboratories conducted the studies of precision. Six, 16, and 13 of these met the allowable targets for Na, K, and Cl, respectively. The precision was particularly poor for Na. Many laboratories did not meet the allowable targets for intercepts or slopes of regression equations, or for the mean differences between 1 st and 2 nd determinations. Seventeen laboratories carried out the confirmation of maintenance of precision study. All of these met the allowable targets for K, but 3 of these did not meet the allowable targets for Na and Cl. These findings indicate that more extensive control of assays is needed to obtain precision of Na and Cl measurement that is as good as that of K. The quantitative analysis of factors changing precision revealed that factors changing day-to-day assay measurements were greater than those changing within-day assay measurenents of Na, though in the case of K and Cl, factors changing within-day assay measurenents were greater than those changing day-to-day assay measurenents. Of factors changing within-day assay measurenents and factors changing day-to-day assay measurenents, factors changing in the short-term were regarded as relatively important compared to factors changing in the long-term. The existence of considerable bias was revealed from measursment of working certified reference sera. By using equations for correction derived from the certified values and the values determined in the laboratories, the magnitude of the bias decreased by about one severalth. However, in some laboratories, the correction did not seem to work well owing to poor precision. Also, the studies of pooled sera indicate that the above-mentioned procedures were effective in decreasing the differences between laboratory data.<BR>These results suggest that the means used in this trial are useful in unifying measured values of serum electrolytes.