Quality assurance in the pre-analytical phase of human urine samples by (1)H NMR spectroscopy.
Metabolomic approaches investigate changes in metabolite profiles, which may reflect changes in metabolic pathways and provide information correlated with a specific biological process or pathophysiology. High-resolution (1)H NMR spectroscopy is used to identify metabolites in biofluids and tissue samples qualitatively and quantitatively. This pre-analytical study evaluated the effects of storage time and temperature on (1)H NMR spectra from human urine in two settings. Firstly, to evaluate short time effects probably due to acute delay in sample handling and secondly, the effect of prolonged storage up to one month to find markers of sample miss-handling. A number of statistical procedures were used to assess the differences between samples stored under different conditions, including Projection to Latent Structure Discriminant Analysis (PLS-DA), non-parametric testing as well as mixed effect linear regression analysis. The results indicate that human urine samples can be stored at 10 °C for 24 h or at -80 °C for 1 month, as no relevant changes in (1)H NMR fingerprints were observed during these time periods and temperature conditions. However, some metabolites most likely of microbial origin showed alterations during prolonged storage but without facilitating classification. In conclusion, the presented protocol for urine sample handling and semi-automatic metabolite quantification is suitable for large-scale epidemiological studies.
Institute of Clinical Chemistry and Laboratory Medicine, University of Greifswald, Ferdinand-Sauerbruch-Straße NK, 17475 Greifswald, Germany.
Kathrin
K
Budde
Medical Center - University of Freiburg, Berliner Allee 29, 79110 Freiburg, Germany.
Ömer-Necmi
ÖN
Gök
Institute of Clinical Chemistry and Laboratory Medicine, University of Greifswald, Ferdinand-Sauerbruch-Straße NK, 17475 Greifswald, Germany.
Maik
M
Pietzner
Institute of Epidemiology II, Helmholtz Zentrum Munich, German Research Center for Environmental Health, 85764 Neuherberg, Germany.
Christine
C
Meisinger
Department of Epidemiology and Preventive Medicine, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany.
Michael
M
Leitzmann
Institute of Clinical Chemistry and Laboratory Medicine, University of Greifswald, Ferdinand-Sauerbruch-Straße NK, 17475 Greifswald, Germany; DZHK (German Centre for Cardiovascular Research), Greifswald Partner Site, Greifswald, Germany.
Matthias
M
Nauck
Medical Center - University of Freiburg, Berliner Allee 29, 79110 Freiburg, Germany.
Anna
A
Köttgen
Institute of Clinical Chemistry and Laboratory Medicine, University of Greifswald, Ferdinand-Sauerbruch-Straße NK, 17475 Greifswald, Germany; DZHK (German Centre for Cardiovascular Research), Greifswald Partner Site, Greifswald, Germany. Electronic address: nele.friedrich@uni-greifswald.de.
Nele
N
Friedrich
D000328:Adult; D000368:Aged; D015925:Cryopreservation; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007668:Kidney / Q000503:physiopathology; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D055432:Metabolomics / Q000379:methods*; D008875:Middle Aged; D011786:Quality Control; D013997:Time Factors; D016482:Urinalysis / Q000379:methods*; D055815:Young Adult
(1)H NMR spectroscopy; Metabolome; Preanalytic; Quality assurance