The effects of transportation on RNA, quantity, quality and transcript stability. Adult blood from one healthy donor was collected in Tempus™ tubes (n = 20). Samples were divided randomly into five groups (n = 4 tubes per group): four groups were sent by standard mail to four different hospitals in Norway, and the fifth group was kept at NIPH (Oslo/lab). Temperature was monitored during transportation. A) The effects of transportation on RNA quality and yield; B) The effects of transportation on RNA transcript levels of six genes. Samples kept at NIPH were used as reference samples; hence all other samples were compared against the reference samples. Each bar represents the average log2-transformed fold change values and the error bar indicates ± SE. The dashed lines indicate ± 2 – fold change.