title: Measurement of insulin-like growth factor-1 and insulin-like growth factor binding protein-3 after delayed separation of whole blood samples.
abstract: OBJECTIVE
  Epidemiological studies benefit from unbiased blood specimens collected with minimal cost and effort of blood collection and storage. We evaluated the stability of IGF-1 and IGFBP-3 in whole blood samples stored at room temperature to justify delays in blood processing.
  
  
  METHODS
  Total IGF-1 and IGFBP-3 levels were measured in EDTA plasma (n=12), heparin plasma (n=12) and serum (n=10) samples of healthy volunteers after blood processing delays up till 14 days. Stability of measured IGF-1 and IGFBP-3 levels was tested by paired t-test and a linear mixed effect model.
  
  
  RESULTS
  Longitudinal analysis showed that IGF-1 levels were not significantly affected by blood processing delays in EDTA tubes (p=0.18) and IGFBP-3 levels were marginally stable (p=0.06). In heparin plasma and serum, however, IGF-1 increased over time of delayed processing and IGFBP-3 levels tended to decrease (p<0.01).
  
  
  CONCLUSIONS
  Total IGF-1 and IGFBP-3 levels are stable in whole blood collected in EDTA tubes at room temperature up till 7 days, allowing a delay in blood processing to reduce costs in large multi-center studies.
authors.affiliation: Department of Medical Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Hermien
authors.initials: H
authors.lastname: Hartog
authors.forename: Winette T A
authors.initials: WT
authors.lastname: van der Graaf
authors.forename: Jelle
authors.initials: J
authors.lastname: Wesseling
authors.forename: Eveline
authors.initials: E
authors.lastname: van der Veer
authors.forename: H Marike
authors.initials: HM
authors.lastname: Boezen
mesh_terms: D000328:Adult; D001781:Blood Component Removal / Q000592:standards; D001800:Blood Specimen Collection / Q000592:standards*; D004355:Drug Stability; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000032:analysis / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000378:metabolism*; D008137:Longitudinal Studies; D008875:Middle Aged; D013997:Time Factors
chemical_list: D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I