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.