title: Short-term storage of blood samples and DNA isolation in serum separator tubes for application in epidemiological studies and clinical research.
abstract: OBJECTIVE
  To investigate the use of a simple DNA isolation technique for application in epidemiologic studies. To analyze systematically the potential impact of lag time between blood drawing and DNA isolation and the condition of storage of blood samples on the quantity and quality of isolated DNA in large-scale epidemiologic studies.
  
  
  METHODS
  A modified single tube DNA isolation technique was used. DNA was isolated from samples collected from six participants and processed in triplicate: a) without delay after blood drawing; b) after blood cells were stored at 4 degrees C for 7 days; c) after blood cells were stored at -70 degrees C for 7 days; and d) after storage for 7 days at -70 degrees C with addition of lysis/digestion buffer. Polymerase chain reaction (PCR) and Southern blot analysis were performed to analyze the quality of the isolated DNA.
  
  
  RESULTS
  The average amount of DNA isolated ranged from 27.0 to 71.1 microg/4.5 ml whole blood. Storage at 4 degrees C yielded, on the average, 20% less DNA than the samples processed without delay or after storage at -70 degrees C, although this difference was not statistically significant. All four conditions studied allowed isolation of highly pure DNA suitable for genetic analyses by Southern blot analysis and polymerase chain reaction.
  
  
  CONCLUSIONS
  This pilot study suggests that storage for 7 days and at different temperatures allows isolation of high quality DNA. Using the described technique, storage of up to 7 days permits processing of large numbers of samples (50-70) in a single day, allowing for a reliable and cost-efficient way of processing in various settings. Further studies are needed to investigate the influence of long-term storage of biological specimens on DNA isolation and quality.
authors: Department of Medicine, State University of New York, Buffalo, NY 14214, USA.
authors: H J
authors: HJ
authors: Schünemann
authors: M
authors: M
authors: Stanulla
authors: M
authors: M
authors: Trevisan
authors: P D
authors: PD
authors: Aplan
authors: J L
authors: JL
authors: Freudenheim
authors: P
authors: P
authors: Muti
mesh_terms: D001771:Blood Banks; D003363:Cost Control; D004247:DNA / Q000235:genetics / Q000302:isolation & purification*; D016021:Epidemiologic Studies; D005828:Genetics, Population; D006801:Humans; D010865:Pilot Projects; D011786:Quality Control; D013048:Specimen Handling; D013696:Temperature
chemical_list: D004247:DNA