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White Paper

White Paper: Freezing Blood Samples for Deferred Immunophenotyping


A study conducted by the Canadian Clinical Research Organisation (CRO), Caprion found that whole blood samples stored in Cytomark's TransFix/EDTA Vacuum Blood Collection tubes (TVT) are suitable for immunophenotyping after being frozen at -80°C. Caprion also observed that a competing product, Streck's Cyto-Chex Blood Collection Tubes (BCT), were not useable after storage at -80°C.

Cytomark performed a short study to determine whether Caprion's findings could be replicated. This study used the TVTs and BCTs to compare the immunophenotype of fixed peripheral whole blood samples at time zero, and after freezing at -80°C for 7 days. The structural integrity of the frozen TVTs and BCTs were also examined. Optimisation of storage conditions was further investigated to improve immunophenotyping after freezing.

TVTs showed the best cell percentage differences from the control with average lymphocyte cell recovery of 77% compared to 26% for the BCTs. All three BCTs cracked during the freezing process while all of the TVTs remained intact. Storage optimisation experiments showed tubes frozen at an angle and thawed at 37°C performed best overall.

These results raise the possibility that whole blood samples for immunophenotyping may be stored at -80°C for extended periods beyond 7 days. Further studies will aim to demonstrate the upper limit of time the sample will remain stable and suitable for immunophenotyping. Experiments will also be conducted to examine the suitability for use in phosphoflow assays.

Download the White Paper (pdf)

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