LC/MS Based Monitoring of Endogenous Decay Markers for Quality Assessment of Serum Specimens
- *Corresponding Author:
- Peter Findeisen
MD, Institute for Clinical Chemistry
Medical Faculty Mannheim of the University of Heidelberg
Theodor-Kutzer-Ufer 1, 68167 Mannheim, Germany
Tel: +49-621 383 3483
Fax: +49-621 383 3819
Received date: February 26, 2015; Accepted date: April 30, 2015; Published date: May 04, 2015
Citation: Thumfart JO, Abidi N, Mindt S, Costina V, Hofheinz R, et al. (2015) LC/ MS Based Monitoring of Endogenous Decay Markers for Quality Assessment of Serum Specimens. J Proteomics Bioinform 8:091-097. doi:10.4172/jpb.1000356
Copyright: © 2015 Thumfart JO, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Introduction: Preanalytical variations have major impact on most biological assays. Specifically MS-based multiparametric proteomics analyses of blood specimens are seriously affected by limited protein stability due to high intrinsic proteolytic activity of serum and plasma. However, the direct analysis of sample quality (DASQ) for serum specimens is not readily available. Here we propose the mass spectrometry based monitoring of peptide patterns that are ex vivo changing in a time dependent manner to alleviate these constrains.
Materials and methods: Serum specimens from healthy controls (n=3) and patients with colorectal cancer were analyzed for a set of endogenous peptides (n=62). The respective proteolytic fragments were monitored with LC/MS at different preanalytical points in time ranging from 1 h to 48 h after blood withdrawal. An algorithm was constructed with a training set of serum specimens from colorectal cancer patients (n=30). An independent test set of patients (n=20) was used for further validation.
Results: The coefficient of determination (R2) for the linear regression of true and estimated points in time was 0.89. However, the classification accuracy for specimens with a preanalytical time span below 8 h was higher when compared to older specimens (>8 h).
Conclusion: Endogenous peptides are processed in blood specimens in a time dependent manner. This ‘proteomic degradation clock’ can be used to estimate the preanalytical quality of serum specimens. This is specifically relevant prior to in depth proteomic profiling approaches or other laborious analyses in research or diagnostic applications. Accordingly, specimens with low quality can be identified and subsequently be excluded from further analyses to avoid any unwanted preanalytical bias.