Gowans E M, Fraser C G
Clin Chem. 1987 Jun;33(6):847-50.
Analytical, intra-individual, and interindividual components of variation for sodium, potassium, urea, creatinine, calcium, and phosphate were estimated from results for 24-h urine specimens collected from 15 apparently healthy individuals every four weeks for 40 weeks. Expressed as output, mean values differed for men and women, except for calcium. Our data on intra-individual variation were similar to those obtained for 10 men by Shephard et al. (Clin Chem 1981;27:569-73). Calculated analytical goals are easily attained by current methods. Reference values for urine creatinine are useful only when expressed as output and stratified according to gender. The ratios of intra- to interindividual variation generally increase on such stratification; separate reference values for men and women are therefore required for analytes expressed as output. Measurements of sodium and potassium in urine should be reported as concentration, but output terms are favored for the other analytes. Differences for two serial results from an individual must be rather large to differ statistically.
通过对15名看似健康的个体每四周收集一次、持续40周的24小时尿液标本结果进行分析，估算了钠、钾、尿素、肌酐、钙和磷酸盐的分析变异、个体内变异和个体间变异成分。以输出量表示时，除钙外，男性和女性的平均值存在差异。我们关于个体内变异的数据与Shephard等人（《临床化学》1981年；27:569 - 73）对10名男性所获得的数据相似。当前方法很容易实现计算得出的分析目标。尿肌酐的参考值只有在以输出量表示并按性别分层时才有用。在这种分层情况下，个体内变异与个体间变异的比率通常会增加；因此，对于以输出量表示的分析物，需要分别给出男性和女性的参考值。尿钠和尿钾的测量结果应以浓度形式报告，但其他分析物则更倾向于使用输出量术语。个体两次连续检测结果的差异必须相当大才有统计学意义。
