露点と凝固点による浸透圧測定の比較

Comparison of Dewpoint and Freezing Point Osmometry

　32の透明な血清と23の尿の浸透圧を露点と凝固点浸透圧計で計った．得られた回帰方程式は，露点＝0.96×凝固点＋7.6で，相関係数は0.99であった．両法によって分析された32の透明な血清の平均値に有意の差はなかったが，14の乳び血清では，露点法の平均が291.6，凝固点法の平均が284.1と露点値が高かった．正常プール血清による日差変動のCVは，凝固点計で1.04，露点計で2.38となった．結果は露点法では乳び血清で注意して用いられるべきことを示した．

　Osmolality^*1 was measured on 32 clear serum samples and on 23 urines, with dewpoint^*2 and with freezing point osmometers. The observed^*3 regression equation was dewpoint=0.96 freezing point+7.6, with a correlation coefficient of 0.99. The observed mean for 32 clear sera analyzed by both methods was not significantly different. However, when 14 lipemic sera were analyzed, the dewpoint measurements were higher : X dewpoint=291.6 ; X freezing point=284.1. The between-run standard deviation^*4 observed for a normal serum pool yielded a coefficient of variation of 1.04 with the freezing point and 2.38 with the dewpoint instrument. Results indicate that the dewpoint device should be used with caution for lipemic serum samples.