Relevance of pre-analytical factors in multiomics: Toward a standardized blood processing protocol

To implement multiomic studies successfully, there is a need to overcome challenges in steps ranging from study design to data integration. As blood is the preferred matrix for sampling in such studies, we review how pre-analytical factors affect genomics, transcriptomics, proteomics, and metabolomics and propose a harmonized blood processing protocol. Plasma is preferred, as clotting of serum may cause contamination from lysed cells. Transcriptomics is highly sensitive to platelet contamination, making platelet-poor plasma ideal. Processing delays and room-temperature storage compromise the stability of several analytes classes. To ensure comparability, the Standard PREanalytical Code (SPREC) should document all phases of sample handling. We recommend collecting blood in K2EDTA tubes and separating plasma via two centrifugations (1600×g and 16,000×g, 10 min at 4 °C). Samples should be checked for hemolysis, icterus, and lipemia and then stored at −80 °C [SPREC: PL2.PED.A1.C.J.A.D]. Following this standardized protocol or documenting deviations from it can improve multiomic reproducibility.