Urine molecular profiling distinguishes health and disease: new methods in diagnostics? Focus on UPLC-MS

Urine may be a waste product, but it contains an enormous amount of information. Its role in diagnostics cannot be underestimated. The combination of high-end analytical technology with multivariate statistics allows differential analysis of replicate samples with applications for both high- and low-molecular-weight analytes, namely proteins and metabolites. Global urine profiles measured with NMR or mass spectrometry (MS)-based methods distinguish, for example, individuals, health status and hormonal changes. They do not necessarily discriminate between substance classes but investigate method-determined subgroups, such as all compounds separated by reversed-phase liquid chromatography. For diagnostics, the identification of those compounds is of secondary interest because the overall features of the profile itself are used for sample comparison. The potential of this simple approach for clinical diagnostics is huge, since only minimal urine preparation (e.g., centrifugation and filtration for liquid chromatography-MS) is necessary and the experimental execution using, for instance, technologies such as ultra-performance liquid chromatography coupled with high-end MS can be standardized. However, concerted collaborative efforts are required to generate comparable datasets and to create the profile database necessary for diagnostic applications.