title: A determination of the pre-analytical storage conditions for insulin like growth factor-I and type III procollagen peptide.
abstract: OBJECTIVE
  IGF-I and type III procollagen (P-III-P) have been proposed as markers to detect GH abuse. This study aims to determine whether the pre-analytical storage temperature or delayed centrifugation affect the measured IGF-I and P-III-P concentrations.
  
  
  METHODS
  Observational study.
  
  
  METHODS
  Wellcome Trust Clinical Research Facility, Southampton.
  
  
  METHODS
  Nineteen healthy volunteers.
  
  
  METHODS
  Blood was collected into bottles containing a clotting agent, lithium heparin or EDTA. One sample from each group was centrifuged and stored at -80 degrees C (control sample). The remaining samples from each group were stored as either serum or whole blood at 4 degrees C or room temperature for up to five days prior to storage at -80 degrees C.
  
  
  METHODS
  IGF-I and P-III-P.
  
  
  RESULTS
  The storage temperature or timing of centrifugation did not appear to affect IGF-I concentration. In contrast, the measured P-III-P concentration rose by 6.5-7% per day in clotted and lithium heparin samples when stored as whole blood (p<0.006) or serum (6.2-6.5% per day) at room temperature (p<0.001). P-III-P did not change when the samples were stored at 4 degrees C. Although collection into EDTA inhibited the rise in P-III-P, the baseline measured values were significantly higher than in other media and spiking experiments demonstrated that EDTA exerted a significant matrix effect on the assay.
  
  
  CONCLUSIONS
  While the optimum collection method is immediate centrifugation and storage at -80 degrees C, it would seem acceptable to store serum or clotted blood samples at 4 degrees C, but not ambient temperature, for up to five days. It is incumbent on the anti-doping authorities to provide facilities to allow this.
authors.affiliation: Endocrinology and Metabolism Sub-Division, Developmental Origins of Adult Health and Disease Division, School of Medicine, University of Southampton, Southampton General Hospital, Southampton, United Kingdom. R.I.G.Holt@soton.ac.uk
authors.forename: Richard I G
authors.initials: RI
authors.lastname: Holt
authors.forename: Ioulietta
authors.initials: I
authors.lastname: Erotokritou-Mulligan
authors.forename: Sean A
authors.initials: SA
authors.lastname: Ridley
authors.forename: Cathy M
authors.initials: CM
authors.lastname: McHugh
authors.forename: E Eryl
authors.initials: EE
authors.lastname: Bassett
authors.forename: David A
authors.initials: DA
authors.lastname: Cowan
authors.forename: Christiaan
authors.initials: C
authors.lastname: Bartlett
authors.forename: Peter H
authors.initials: PH
authors.lastname: Sönksen
mesh_terms: D001793:Blood Preservation / Q000379:methods*; D001800:Blood Specimen Collection / Q000379:methods*; D024061:Collagen Type III / Q000097:blood / Q000737:chemistry*; D004492:Edetic Acid / Q000737:chemistry; D006493:Heparin / Q000737:chemistry; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000737:chemistry*; D013696:Temperature
chemical_list: D024061:Collagen Type III; D007334:Insulin-Like Growth Factor I; D006493:Heparin; D004492:Edetic Acid