BACKGROUND The urea creatinine ratio (UCR) is important in the clinical assessment of several medical conditions, including acute kidney injury and gastrointestinal bleeding. However, accurate and robust paediatric reference intervals (RIs) for this ratio have not been well established. Here, we determined age- and sex-specific discrete and continuous RIs for UCR in the Canadian Laboratory Initiative on Paediatric Reference Intervals (CALIPER) cohort of healthy children and adolescents for the first time. METHODS UCR was calculated for approximately 1030 CALIPER participants using retrospective urea and creatinine (both Jaffe and enzymatic methods) normative data. Partitions were determined using the Harris & Boyd statistical method. Discrete RIs were established in accordance with the Clinical and Laboratory Standards Institute (CLSI) guidelines. Continuous RIs were established using nonparametric quantile regression. RESULTS Several age- and sex-specific partitions were necessary to capture dynamic physiological trends associated with this ratio throughout childhood and adolescence, highlighting the benefit of continuous RI establishment. Established UCR RIs also demonstrated marked differences between Jaffe and enzymatic assay methods. CONCLUSION Our results clearly demonstrate the critical need for RI stratification by important covariates such as age, sex, and creatinine assay methodology for paediatric UCR test result interpretation. These data contribute to our understanding of normative UCR values in childhood and adolescence and can be expected to improve paediatric test result interpretation in clinical laboratories that report this ratio.

中文翻译：

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健康儿童和青少年尿素肌酐比率的CALIPER儿科参考​​区间。

背景技术尿素肌酐比率（UCR）在几种医学状况的临床评估中很重要，包括急性肾损伤和胃肠道出血。但是，还没有很好地建立针对该比率的准确且健壮的儿科参考区间（RI）。在这里，我们首次在健康儿童和青少年的加拿大儿科参考间隔实验室计划（CALIPER）队列中确定了UCR的年龄和性别特定的离散和连续RI。方法使用回顾性尿素和肌酐（Jaffe法和酶法）的标准化数据，为大约1030名CALIPER参与者计算UCR。使用Harris＆Boyd统计方法确定分区。离散RI是根据临床和实验室标准协会（CLSI）指南建立的。使用非参数分位数回归来建立连续RI。结果在整个儿童期和青春期中，有几个特定年龄和性别的分区对于捕获与此比例相关的动态生理趋势是必要的，从而突出了连续进行RI的益处。既定的UCR RIs也证明了Jaffe和酶促测定方法之间的显着差异。结论我们的结果清楚地表明，通过年龄，性别和肌酐分析方法等重要协变量来进行儿科UCR测试结果解释，对RI分层至关重要。