Table 2 Critical parameters for epigenome-wide association studies
From: Letter to the editor: blood processing and sample storage have negligible effects on methylation
Parameter | How to address | |
|---|---|---|
Inter-individual variability | Sex | Appropriate inclusion and exclusion criteria; record information; statistical corrections |
Age | ||
Diet and lifestyle | ||
Alcohol consumption | ||
Medication use | ||
Variability in the sample | Leukocyte counts and composition | Determine leukocyte counts and cell-composition at sample collection and adjust methylation data accordingly |
Variability introduced through processing | Changes in leukocyte counts with prolonged storage of whole blood | Determine leukocyte counts and cell-composition immediately or as soon as possible after sample collection |
Efficiency of bisulphite conversion | Include commercially available standards in the conversion reaction to determine conversion efficiency and include technical replicates | |
DNA integrity post-bisulphite conversion | Assess DNA integrity post-conversion with a multiplex PCR assay | |