title: Serum and plasma fragments of C-telopeptides of type I collagen (CTX) are stable during storage at low temperatures for 3 years.
abstract: BACKGROUND
  Control of pre-analytical variables is essential for successful application of biological markers, including bone resorption markers, in clinical trials and routine use. The effect of storage temperature on stability of bone resorption markers have not been subject of systematically investigation, and therefore the present study was set out to determine the stability of C-telopeptides of type I collagen (CTX) in serum and plasma samples stored frozen for 3 years.
  
  
  METHODS
  The serum and plasma levels of CTX were determined in samples aliquoted and stored frozen for up to 3 years.
  
  
  RESULTS
  No significant decrease could be detected in neither serum nor plasma samples after 3 years of storage at -20, -80 or -150 degrees C. However, at elevated temperature, i.e. 4 and 37 degrees C, improved stability of CTX was observed in EDTA plasma samples compared to serum.
  
  
  CONCLUSIONS
  CTX is stable in frozen serum and plasma samples for up to 3 years. EDTA plasma might be the preferred matrix due to improved stability at elevated temperatures.
authors.affiliation: Nordic Bioscience A/S, Herlev Hovedgade 207, DK-2730 Herlev, Denmark. pq@nordicbioscience.com
authors.forename: P
authors.initials: P
authors.lastname: Qvist
authors.forename: M
authors.initials: M
authors.lastname: Munk
authors.forename: N
authors.initials: N
authors.lastname: Hoyle
authors.forename: C
authors.initials: C
authors.lastname: Christiansen
mesh_terms: D015415:Biomarkers / Q000032:analysis; D001862:Bone Resorption / Q000097:blood / Q000652:urine; D003080:Cold Temperature; D003094:Collagen / Q000097:blood*; D024042:Collagen Type I; D004492:Edetic Acid / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D010455:Peptides / Q000097:blood*; D010949:Plasma / Q000737:chemistry*; D044967:Serum / Q000737:chemistry*; D013048:Specimen Handling / Q000379:methods*; D013696:Temperature; D013997:Time Factors
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D003094:Collagen; D004492:Edetic Acid