Utility of Capillary Blood in Gene Expression Studies

The FAA Functional Genomics Team examined the feasibility of analyzing gene expression profiles using capillary blood collected by fingerstick, with the goal of developing practical fingerstick blood collections to expand blood collection capabilities and allow large-scale or field-based collections. We compared the RNA sequencing results obtained from two different capillary blood collection and RNA extraction methods with the results obtained from a standard venous blood collection and RNA extraction protocol. We also compared capillary blood processing methods, as well as fingerstick locations, within one capillary collection/extraction method. Within each method we sought to distinguish male from female participants to assess the capacity of each collection/extraction method for gene expression profiling. The study population included 40 participants aged 18-60 who were free from any acute illness or any illness that would preclude blood collection. We determined that capillary blood possesses large-scale significant differences from venous blood and that the two capillary methods produced similar gene expression profiles. We further determined that all methods were useful for detecting gene expression differences between assessed groups (male and female participants in this case). We conclude that capillary blood is suitable for gene expression profiling in quantities as low as 100 μL whole blood, but recommend that researchers should rely on a single blood collection method if they desire to compare results between individual studies. Raw sequencing files (.fastq) from this study are available in dbGaP.]]>