Theophylline can be determined with an analytical element and method which utilize the inhibition, by theophylline, of alkaline phosphatase activity on an appropriate substrate. The assay is carried out at a pH of 9 or less. The element contains a suitable buffer and first and second zones in fluid contact. The isoenzyme of alkaline phosphatase and a suitable substrate for the isoenzyme are located in different zones of the element. The isoenzyme is present in one of the zones in an amount of at least 100 I.U./m². This level of isoenzyme reduces or eliminates bias caused by endogenous alkaline phosphatase and hemoglobin during an assay.
茶碱可以用一种分析元素和方法来测定,这种元素和方法利用茶碱对适当底物上碱性
磷酸酶活性的抑制作用。检测在 pH 值为 9 或更低的条件下进行。检测元件包含合适的缓冲液以及液体接触的第一区和第二区。碱性
磷酸酶同工酶和该同工酶的适当底物位于该元件的不同区域。其中一个区中的同工酶含量至少为 100 I.U./m²。这种
水平的同工酶可减少或消除化验过程中内源性碱性
磷酸酶和血红蛋白造成的偏差。