Banking of clinical samples for proteomic biomarker studies: a consideration of logistical issues with a focus on pre-analytical variation.

Biobanks with their collections of clinical samples and data are essential resources for the success of clinical proteomics in delivering and validating candidate biomarkers. Samples must be banked in a manner that allows maximum subsequent compatibility with analytical techniques and additionally many critical factors must be taken into account when establishing a biobank or selecting samples from a biobank. These include logistical, ethical, legal and security issues and, very importantly, steps to minimise any pre-analytical variability introduced through sample processing and handling (technical effects). The inherent variation present within the samples must also be taken into account. In this review, we examine the impact of these factors and issues to be faced when banking samples with a particular focus on sources of pre-analytical variation, which must be rigorously controlled and recorded. It is encouraging that several initiatives are now addressing such key issues and these are also discussed.