State of the art in preservation of fluid biospecimens.

Fluid biospecimens (blood, serum, urine, saliva, cerebrospinal fluid and bronchial lavage fluid) contain not only cells and subcellular components, but also proteins, enzymes, lipids, metabolites, and peptides, which are utilized as biomarkers. Availability of high-quality biospecimens is a requirement for biomarker discovery. The quality of the biospecimens depends upon preanalytical variables (ie, collection and processing techniques, freeze/thaw stability, and storage stability), which account for >60%-90% of the diagnostic errors. Currently, millions of fluid biospecimens are stored in hundreds of biorepositories across the nation, and tens of thousands of new biospecimens are added to the pool daily. Specimen stabilization is imperative, because fluid biospecimens degrade quickly when kept untreated at room temperature. Achieving a high-quality fluid biospecimen requires understanding the effects of storage processing parameters (eg, freezing and thawing as well as cryo-/lyoprotectant additives) and storage conditions on biomarkers contained within the biospecimens. In this article, we will discuss the main issues related to the stabilization of specific biofluids by reviewing (a) the current preservation and storage practices applied in biobanks/biorepositories and (b) the sensitivity of certain biomarkers to current storage techniques.