title: Long-term storage of blood RNA collected in RNA stabilizing Tempus tubes in a large biobank--evaluation of RNA quality and stability.
abstract: BACKGROUND
  Establishing methods for secure long term storage of RNA is critical to realizing the promise of biobanks in biomedical research. Here, we describe the results of yearly analyses of the same set of umbilical cord and adult whole blood RNA collected in Tempus Blood RNA tubes and stored at -80 °C, over a period of up to six years. We systematically investigated the effects of long-term storage of samples (75 Tempus tubes form three adult donors and 30 Tempus tubes from three cord blood donors) on the RNA quality and transcript stability of six selected genes (CDKN1A, FOS, IL1B, IL8, MYC and TP53). This is the first systematic study of both cord and adult blood samples stored for many years.
  
  
  RESULTS
  The RNA purity and integrity, expressed as RIN-values, were stable up to six years of storage, and there were no storage-related deleterious effects on RNA purity. There were limited intra- and inter-individual variations in RNA yields; however, no consistent trend of decreasing RNA yield was observed with the duration of storage. Some long-term storage effects were found on the relative transcript levels of the six genes when compared to the year 0 samples. However, these changes were within ± 2-fold for both types of blood samples, except for two genes. Our results show that storage of these samples for up to six years did not have significant effects on the RNA quality and transcript stability of the six genes.
  
  
  CONCLUSIONS
  Blood RNA is stable in Tempus tubes stored at -80 °C over a period of six years. Intact and good-quality RNA suitable for transcript profiling analyses in epidemiological studies was obtained from blood samples stored in Tempus tubes. This suggests that blood samples collected in large biobanks-such as the Mother and Child (MoBa) Cohort at Norwegian Institute of Public Health (NIPH) and frozen in suitable collection tubes for total RNA stabilization, can be used for quantitative studies after at least six years of storage.
authors.affiliation: The Norwegian Institute of Public Health, PO Box 4404, Nydalen, NO-0403, Oslo, Norway. nur.duale@fhi.no.
authors.forename: Nur
authors.initials: N
authors.lastname: Duale
authors.forename: W Ian
authors.initials: WI
authors.lastname: Lipkin
authors.forename: Thomas
authors.initials: T
authors.lastname: Briese
authors.forename: Jeanette
authors.initials: J
authors.lastname: Aarem
authors.forename: Kjersti S
authors.initials: KS
authors.lastname: Rønningen
authors.forename: Kaja K
authors.initials: KK
authors.lastname: Aas
authors.forename: Per
authors.initials: P
authors.lastname: Magnus
authors.forename: Kari
authors.initials: K
authors.lastname: Harbak
authors.forename: Ezra
authors.initials: E
authors.lastname: Susser
authors.forename: Gunnar
authors.initials: G
authors.lastname: Brunborg
mesh_terms: D000328:Adult; D001771:Blood Banks; D005312:Fetal Blood / Q000378:metabolism; D006801:Humans; D009664:Norway; D012313:RNA / Q000097:blood*; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D012313:RNA