title: Blood storage at 4 degrees C-factors involved in DNA yield and quality.
abstract: BACKGROUND
  Whole blood provides one of the most common sources of both high-quality DNA and high-quantity DNA for molecular biological purposes. Typically, blood storage at 4 degrees C is short term, which ranges from a few days to a few weeks. However, long-term storage usually involves blood being frozen, with a resultant loss in DNA yield. The authors examined the effects of long-term storage at 4 degrees C.
  
  
  METHODS
  Duplicate blood samples were collected from 301 participants (aged 20-98 years) enrolled as part of ongoing studies. Samples were stored at 4 degrees C for between 11 days and 922 days, and DNA was subsequently extracted using a phenol/chloroform procedure.
  
  
  RESULTS
  A negative correlation of the number of storage days existed at 4 degrees C with DNA yield. The main determinant on DNA yield was the age of the participant in the study, with older persons having a lower DNA yield.
  
  
  CONCLUSIONS
  Long-term storage of blood at 4 degrees C does have a detrimental effect on DNA yield, but this effect seemed less significant than the age of a person. The impact of age of a person or storage time has a minimal impact on DNA quality. Therefore, storage of blood at 4 degrees C offers an acceptable alternative to frozen storage.
authors.affiliation: Centre for Eye Research Australia, University of Melbourne, East Melbourne, Australia. andreajr@unimelb.edu.au
authors.forename: Andrea J
authors.initials: AJ
authors.lastname: Richardson
authors.forename: Niro
authors.initials: N
authors.lastname: Narendran
authors.forename: Robyn H
authors.initials: RH
authors.lastname: Guymer
authors.forename: Hien
authors.initials: H
authors.lastname: Vu
authors.forename: Paul N
authors.initials: PN
authors.lastname: Baird
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001793:Blood Preservation; D002725:Chloroform; D003080:Cold Temperature; D015925:Cryopreservation; D004247:DNA / Q000302:isolation & purification*; D006801:Humans; D008875:Middle Aged; D008967:Molecular Biology / Q000379:methods* / Q000592:standards; D019800:Phenol; D012997:Solvents
chemical_list: D012997:Solvents; D019800:Phenol; D002725:Chloroform; D004247:DNA