Background: Cytokine concentrations in transfused blood components are of interest for some clinical trials. It is not always possible to process samples of transfused components quickly after their administration. Additionally, it is not practical to sample material in an acceptable manner from many bags of components before transfusion, and after transfusion, the only representative remaining fluid of the component may be that in the "segment," because the bag may have been completely transfused. Multiplex array technology allows rapid simultaneous testing of multiple analytes in small-volume samples. This technology was used to measure white blood cell (WBC) cytokine levels in blood products to determine 1) whether concentrations in segments correlate with those in the main bag and, thus, whether segments could be used for estimation of the concentrations in the transfused component and 2) whether concentrations after sample storage at 4 degrees C for 24 hours do not differ from concentrations before storage, thus allowing for processing within 24 hours, rather than immediately after transfusion.
Study design and methods: WBC cytokines were measured in the supernatant from bags and segments of leukoreduced red blood cells (RBCs), nonleukoreduced whole blood, and leukoreduced plateletphereses using a human cytokine array kit (ProteoPlex, Novagen).
Results: Cytokine concentrations in RBCs and whole blood or plateletphereses stored at 4 degrees C did not differ between bag and segment samples (all p > 0.05). There was no evidence of systematic differences between segment and bag concentrations. Cytokine concentrations in samples from plateletphereses did not change within 24 hours storage at 4 degrees C.
Conclusion: Samples from either bag or segment can be used to study cytokine concentrations in groups of blood products. Cytokine concentrations in plateletphereses appear to be stable for at least 24 hours of storage at 4 degrees C and, thus, samples stored with those conditions may be used to estimate the cytokine concentrations of the component at the time of transfusion.