Among all the human biological fluids used for disease biomarker discovery or clinical chemistry, urine stands out. It can be collected easily and noninvasively, it is readily available in large volumes, it is typically free from protein contamination, and it is chemically complex—reflecting a wide range of physiological states and functions. However, the comprehensive metabolomic analysis of urine has been somewhat less studied compared to blood. Indeed, most published metabolomic assays are specifically optimized for serum or plasma. In an effort to improve this situation, we have developed a comprehensive, quantitative MS-based assay for urine analysis. The assay robustly detects and quantifies 142 urinary metabolites including 28 amino acids and derivatives, 17 organic acids, 22 biogenic amines and derivatives, 40 acylcarnitines, 34 lipids, and glucose/hexose, among which 67 metabolites are absolutely quantified and 75 metabolites are semiquantified. All the analysis methods in this assay are based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) using both positive and negative-mode multiple reaction monitoring (MRM). The recovery rates of spiked urine samples at three different concentration levels, that is, low, medium and high, are in the range of 80% to 120% with satisfactory precision values of less than 20%. This targeted metabolomic assay has been successfully applied to the analysis of large numbers of human urine samples, with results closely matching those reported in the literature as well as those obtained from orthogonal analysis via NMR spectroscopy. Moreover, the assay was specifically developed in a 96-well plate format, which enables automated, high-throughput sample analysis. The assay has already been used to analyze more than 1800 urine samples in our laboratory since early 2019.

中文翻译：

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尿液分析的综合靶向代谢组学分析。

在用于疾病生物标志物发现或临床化学的所有人类生物流体中，尿液脱颖而出。它可以轻松，无创地收集，易于大量获取，通常不受蛋白质污染，并且化学性质复杂-反映了广泛的生理状态和功能。但是，与血液相比，对尿液的综合代谢组学分析的研究较少。实际上，大多数已发表的代谢组学测定法都针对血清或血浆进行了优化。为了改善这种情况，我们开发了一种全面的，基于质谱的定量尿液分析方法。该测定法能够可靠地检测和定量142种尿液代谢物，包括28种氨基酸和衍生物，17种有机酸，22种生物胺和衍生物，40种酰基肉碱，34种脂质，和葡萄糖/己糖，其中绝对定量了67种代谢物，半定量了75种代谢物。此测定法中的所有分析方法均基于液相色谱-串联质谱（LC-MS / MS），同时使用正负模式多反应监测（MRM）。三种不同浓度水平（低，中和高）的加标尿样的回收率在80％至120％的范围内，令人满意的精度值小于20％。这种靶向代谢组学测定法已成功应用于大量人尿液样品的分析，其结果与文献报道的结果以及通过NMR光谱从正交分析中获得的结果非常接近。此外，该测定法以96孔板形式专门开发，可实现自动化，高通量样品分析。自2019年初以来，该分析已在我们的实验室中用于分析1800多个尿液样本。