Addressing the problem of inaccuracy of measured 24-hour urine collections due to incomplete collection
Addressing the problem of inaccuracy of measured 24-hour urine collections due to incomplete collection
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DOI：
10.1111/jch.13696
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发表时间：
2019-10-21
影响因子：
2.8
通讯作者：
Gerber, Linda M.
中科院分区：
文献类型：
--
作者：
Mann, Samuel J.;Gerber, Linda M.
24小时尿液采集被广泛认为是评估各种分析物24小时排泄情况的黄金标准。然而，研究表明，30%的排泄物是不完整的，因此低估了真实的24小时排泄量。我们之前验证了一个基于体重、性别、种族和年龄的估计个人24小时肌酐排泄量的公式。这项研究考察了使用24小时尿肌酐估计值与测量值之比对分析物24小时排泄量进行常规校正是否能减轻因采集不足而产生的误导性低值。从一家高血压门诊招募的99名参与者，提交了24小时的尿液收集，以测量肌酐和钠的排泄。根据先前描述的预期24小时肌酐排泄的标准，将尿液收集分为完全收集(n=63)和不完全收集(n=36)。为了调整采集的可能不完整性，然后将测量的24小时值乘以估计的24小时尿肌酐与测量的24小时尿肌酐的比率，对其进行校正。完全采集者平均24小时肌酐排泄量为1682 mg/d。在不完全收集者中，调整前的平均值为1211 mg/d，调整后的平均值为1695 mg/d。同样，完整收集者平均24小时排钠为156mEq/d，调整前为121mEq/d，调整后为171mEq/d。24小时尿液收集不足是一个常见的问题，导致所测量的分析物排泄量的值低得令人误解。使用24小时肌酐排泄量的估计值对24小时尿值进行常规调整，可以极大地缓解人工低的24小时排泄量结果。
The 24-hour urine collection is widely considered the gold standard for assessing 24-hour excretion of various analytes. Yet, studies show that >30% of collections are incomplete and hence understate the true 24-hour excretion. We previously validated an equation for estimating an individual's 24-hour creatinine excretion, based on weight, sex, race, and age. The present study examines whether routinely correcting measured 24-hour excretion of an analyte using the ratio of estimated to measured 24-hour urine creatinine mitigates the misleadingly low values that result from undercollection. Ninety-nine participants, recruited from an outpatient hypertension clinic, submitted a 24-hour urine collection for measurement of creatinine and sodium excretion. The urine collections were dichotomized into complete (n = 63) and incomplete (n = 36) collections based on previously described criteria for expected 24-hour creatinine excretion. To adjust for possible incompleteness of collections, the measured 24-hour values were then corrected by multiplying them by the ratio of estimated to measured 24-hour urine creatinine. The mean 24-hour creatinine excretion was 1682 mg/d among complete collectors. Among incomplete collectors, the mean was 1211 mg/d before and 1695 mg/d after, adjustment. Similarly, mean 24-hour sodium excretion was 156 mEq/d among complete collectors, whereas among incomplete collectors it was 121 mEq/d before and 171 mEq/d after, adjustment. Undercollection of 24-hour urines is a common problem and results in misleadingly low values for excretion of analytes being measured. Routine adjustment of 24-hour urine values using estimated values for 24-hour creatinine excretion can greatly mitigate artifactually low 24-hour excretion results.