title: Preanalysis storage conditions influence the measurement of brain-derived neurotrophic factor levels in peripheral blood.
abstract: BACKGROUND
  Brain-derived neurotrophic factor (BDNF) is a neurotrophin that plays a pivotal role in regulating neuronal function throughout life, and this factor is regarded as a potential biomarker of mental disorders. However, previous studies have suggested that plasma BDNF levels are more variable than serum BDNF levels.
  
  
  METHODS
  We determined the influence of time and temperature on the measurement of peripheral blood BDNF levels. Blood samples were aliquoted into four types of tubes, including tubes containing heparin, ethylenediaminetetraacetic acid (EDTA), and citrate for plasma, and anticoagulant-free tubes for serum. The samples were stored at 4 or 25°C for 0, 1, 2, 4, 6, 24 or 48 h, and the plasma and serum BDNF levels were measured using enzyme-linked immunosorbent assay.
  
  
  RESULTS
  There were interindividual and interanticoagulant compound variability in the plasma BDNF levels. The measured plasma BDNF levels increased over time, whereas the serum BDNF levels remained unchanged. Furthermore, the BDNF levels detected in plasma stored in heparin tubes at 4°C and those for samples stored in EDTA tubes at 25°C were much higher than those of the other samples.
  
  
  CONCLUSIONS
  This study indicates that measurements of plasma BDNF levels are dependent not only on the anticoagulant compounds but also on the storage time and temperature conditions used after blood sampling.
authors.affiliation: Department of Neuropsychiatry, Graduate School of Medicine, Hirosaki University, Hirosaki, Japan.
authors.forename: Shoko
authors.initials: S
authors.lastname: Tsuchimine
authors.forename: Norio
authors.initials: N
authors.lastname: Sugawara
authors.forename: Masamichi
authors.initials: M
authors.lastname: Ishioka
authors.forename: Norio
authors.initials: N
authors.lastname: Yasui-Furukori
mesh_terms: D000328:Adult; D000925:Anticoagulants / Q000494:pharmacology; D001800:Blood Specimen Collection / Q000295:instrumentation / Q000379:methods*; D019208:Brain-Derived Neurotrophic Factor / Q000097:blood*; D019343:Citric Acid / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006493:Heparin / Q000494:pharmacology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010949:Plasma / Q000737:chemistry / Q000187:drug effects; D044967:Serum / Q000737:chemistry / Q000187:drug effects; D013696:Temperature; D013995:Time; D055815:Young Adult
chemical_list: D000925:Anticoagulants; D019208:Brain-Derived Neurotrophic Factor; D019343:Citric Acid; D006493:Heparin; D004492:Edetic Acid