title: Stability of selected serum hormones and lipids after long-term storage in the Janus Serum Bank.
abstract: BACKGROUND
  The potential value of a biobank depends on the quality of the samples, i.e. how well they reflect the biological or biochemical state of the donors at the time of sampling. Documentation of sample quality has become a particularly important issue for researchers and users of biobank studies.
  
  
  OBJECTIVE
  The aim of this study was to investigate the long-term stability of selected components: cholesterol, high density cholesterol (HDLC), low density cholesterol (LDLC), apolipoprotein A1 (apo-A1), apolipoprotein B (apo B), follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), thyroid stimulating hormone (TSH) and free thyroxin (FT4).
  
  
  METHODS
  Samples, stored at -25°C, from 520 men aged 40-49 years at blood sampling distributed in equally sized groups (n=130) according to length of storage, 0, 4, 17 and 29 years, respectively, were used in a cross sectional design. The freshly collected serum samples were used as a reference group to calculate storage related changes.
  
  
  RESULTS
  The differences between fresh samples and samples stored for 29 years were substantial for apo-A1 (+12%), apo-B (+22.3%), HDLC (-69.2%), LDLC (+31.3%), and PRL (-33.5%), while total cholesterol, FSH, LH, TSH and FT4 did not show any significant difference.
  
  
  CONCLUSIONS
  The study showed large differences in serum level of the selected components. The lipids and apolipoproteins were all changed except for total cholesterol. Most hormones investigated (FSH, LH, TSH and FT4) proved to be stable after 29 years of storage while PRL showed sign of degradation. The observed differences are probably due to long-term storage effects and/or external factors (i.e. diet and smoking).
authors.affiliation: Cancer Registry of Norway, Institute of Population-based Cancer Research, Postbox 5313, 0304 Oslo, Norway. Electronic address: randi.gislefoss@kreftregisteret.no.
authors.forename: Randi E
authors.initials: RE
authors.lastname: Gislefoss
authors.affiliation: Cancer Registry of Norway, Institute of Population-based Cancer Research, Postbox 5313, 0304 Oslo, Norway. Electronic address: tom.k.grimsrud@kreftregisteret.no.
authors.forename: Tom K
authors.initials: TK
authors.lastname: Grimsrud
authors.affiliation: Institute of Clinical Biochemistry, Faculty of Medicine, University of Oslo, Post box 4950, 0424 Oslo, Norway; Department of Medical Biochemistry, Oslo University Hospital, Rikshospitalet, Post box 4950, 0424 Oslo, Norway. Electronic address: lamo2@ous-hf.no.
authors.forename: Lars
authors.initials: L
authors.lastname: Mørkrid
mesh_terms: D000328:Adult; D001793:Blood Preservation; D015925:Cryopreservation; D006728:Hormones / Q000097:blood / Q000737:chemistry*; D006801:Humans; D008055:Lipids / Q000097:blood / Q000737:chemistry*; D008297:Male; D008875:Middle Aged; D013074:Sperm Banks / Q000592:standards*
chemical_list: D006728:Hormones; D008055:Lipids
keywords: Biobank; Biomarker; Blood-based epidemiology; Hormones; Lipids; Stability; Temperature