From the Editor's Desk

“Fit-for-purpose” has been a term used extensively when discussing the preservation of biospecimens. A fit-for-purpose preservation protocol is based on the biospecimen and its unique biological properties as well as the downstream analysis to be performed. In spite of the unique nature of fit-for-purpose protocols, core, scientific principles inform the fundamental structure of the protocol and these principles are independent of the specific biospecimen or analytical technique used. Three articles in this issue illustrate these concepts.

An article by Kozlakidis ¹ describes the preservation of peripheral blood mononuclear cells (PBMNCs) for the purpose of extracting RNA. RNA integrity number (RIN) was used as a quality control metric for the protocol. The protocol developed resulted in high quality RNA extraction with the season of collection appearing to play the most significant role in the variation in the RIN measured. The seasonal dependence of RIN values suggests that this assay has significant limitations in terms of its use as a quality control measure but future assays/preservation protocol will benefit from the basic knowledge developed by this study.

In contrast to the previous study, Germann and colleagues ² needed viable PBMNCs for immunological studies. They noted that existing preservation protocols for PBMNCs were not appropriate for the proposed method of analysis. Specifically, they wanted to avoid the use of fetal calf serum (FCS) in the cryopreservation medium. It was hypothesized that FCS may cause unspecific T-cell activation that would alter the immunological studies performed. They were able to achieve high levels of post thaw viability with newly formulated preservation solutions. They also correctly noted that immunological assays used for frozen and thawed cells must be adapted from those used on cells that have been freshly isolated.

Another article in this issue reviews the state of the art in preservation of plasma/serum, urine, saliva, cerebrospinal fluid and bronchoalveolar lavage. ³ For this diverse group of biospecimens, a small number of core scientific principles provide the basic structure for any of the biospecimens described. Ideally, these core principles will permit us to develop preservation protocols for biospecimens that facilitate their use for as many downstream purposes as possible.