Heaney R P, Recker R R
Ann Intern Med. 1985 Oct;103(4):516-21. doi: 10.7326/0003-4819-103-4-516.
Measurements of true calcium absorption fraction in women were evaluated to see how closely calculations based on a single measurement of serum specific activity after administration of an oral calcium tracer might approximate the absorption value derived from the full, double-isotope absorption procedure. True absorption, body size, and miscible pool turnover could together explain better than 93% of the variance in serum calcium specific activity values 5 hours after a tracer-labeled test meal. Because measurement of pool turnover is not available routinely, it was dropped from the model, and a predictor equation was developed that allowed estimation of true absorption from the 5-hour serum specific activity value, height, and weight. These variables explained 90.8% of the variance in the 5-hour values and gave estimates of true absorption with a 95% confidence interval of +/- 0.055. This small range of uncertainty makes the procedure useful in estimating absorption efficiency for calcium therapy in routine clinical practice.
对女性真实钙吸收分数的测量进行了评估，以观察基于口服钙示踪剂后血清比活性单次测量的计算与通过完整的双同位素吸收程序得出的吸收值的接近程度。真实吸收、体型和可混合池周转率共同解释了示踪剂标记测试餐后5小时血清钙比活性值中超过93%的方差。由于池周转率的测量并非常规可用，因此将其从模型中剔除，并开发了一个预测方程，该方程可根据5小时血清比活性值、身高和体重估算真实吸收。这些变量解释了5小时值中方差的90.8%，并给出了真实吸收的估计值，其95%置信区间为±0.055。这种小范围的不确定性使得该程序在常规临床实践中估算钙治疗的吸收效率方面很有用。
