title: Biovariability of plasma adiponectin.
abstract: BACKGROUND
  Adiponectin is a cytokine produced by adipose tissue with insulin sensitising and anti-atherosclerotic effects. Low plasma adiponectin levels are used as a marker of the metabolic syndrome and incipient type 2 diabetes.
  
  
  METHODS
  We carried out a series of studies to determine the short- and long-term variability of plasma adiponectin levels, including diurnal and post-prandial changes. These investigations also included examining the effect of frozen storage on plasma adiponectin levels.
  
  
  RESULTS
  A nested study in 10 overweight subjects with the metabolic syndrome and 10 age- and sex-matched controls showed intra-subject variation in adiponectin levels over a 30-day period of 12.2% and 18.8%, respectively, equivalent to reference change values of 1.7 and 3.6 microg/mL. In non-obese subjects, plasma adiponectin levels varied minimally over a 15-month period (baseline, 8.3+/-2.9 microg/mL vs. +15 months, 8.2+/-3.0 microg/mL, p=0.95) and showed only minor diurnal and post-prandial changes (pre-meal, 8.2+/-3.0 microg/mL vs. 3 h post-prandial, 8.3+/-3.1 microg/mL, p=0.60). The adiponectin assay had an intra-assay variation of 8.8%, with storage at -30 degrees C for 33 months or three cycles of freezing and thawing having no discernible effect on adiponectin levels.
  
  
  CONCLUSIONS
  These results demonstrate that plasma adiponectin levels have relatively low biovariability and that adiponectin can be sampled fasting or non-fasting to provide a reliable marker of insulin resistance and incipient type 2 diabetes.
authors.affiliation: Lipid and Diabetes Research Group, Christchurch Hospital, Christchurch, New Zealand. brett.shand@cdhb.govt.nz
authors.forename: Brett
authors.initials: B
authors.lastname: Shand
authors.forename: Peter
authors.initials: P
authors.lastname: Elder
authors.forename: Russell
authors.initials: R
authors.lastname: Scott
authors.forename: Christopher
authors.initials: C
authors.lastname: Frampton
authors.forename: Jinny
authors.initials: J
authors.lastname: Willis
mesh_terms: D052242:Adiponectin / Q000097:blood*; D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000097:blood; D001793:Blood Preservation; D002940:Circadian Rhythm / Q000502:physiology; D005260:Female; D005615:Freezing; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood*; D008875:Middle Aged; D019518:Postprandial Period; D012016:Reference Values; D015203:Reproducibility of Results
chemical_list: D052242:Adiponectin; D015415:Biomarkers