title: Increased serum transferrin saturation is associated with lower serum transferrin receptor concentration.
abstract: BACKGROUND
  Serum transferrin receptor (sTfR) concentrations are increased in iron deficiency. We wished to examine whether they are decreased in the presence of potential iron-loading conditions, as reflected by increased transferrin saturation (TS) on a single occasion.
  
  
  METHODS
  We compared sTfR concentrations between 570 controls with normal iron status and 189 cases with increased serum TS on a single occasion; these latter individuals may be potential cases of iron overload. Cases and controls were selected from adults who had been examined in the third National Health and Nutrition Examination Survey (1988-1994) and for whom excess sera were available to perform sTfR measurements after the survey's completion. Increased TS was defined as >60% for men and >55% for women; normal iron status was defined as having no evidence of iron deficiency, iron overload, or inflammation indicated by serum ferritin, TS, erythrocyte protoporphyrin, and C-reactive protein.
  
  
  RESULTS
  Mean sTfR and mean log sTfR:ferritin were approximately 10% and 24% lower, respectively, in cases than in controls (P <0.002). Cases were significantly more likely to have an sTfR value <2.9 mg/L, the lower limit of the reference interval, than were controls (odds ratio = 1.8; 95% confidence interval, 1.04-2.37).
  
  
  CONCLUSIONS
  Our results support previous studies that suggested that sTfR may be useful for assessing high iron status in populations.
authors.affiliation: National Center for Health Statistics, Centers for Disease Control and Prevention, Hyattsville, MD 20782, USA.
authors.forename: A C
authors.initials: AC
authors.lastname: Looker
authors.forename: M
authors.initials: M
authors.lastname: Loyevsky
authors.forename: V R
authors.initials: VR
authors.lastname: Gordeuk
mesh_terms: D000328:Adult; D001793:Blood Preservation; D005006:Ethnicity; D005260:Female; D006306:Health Surveys; D006801:Humans; D007501:Iron / Q000097:blood; D019190:Iron Overload / Q000097:blood / Q000208:ethnology; D008297:Male; D008875:Middle Aged; D011990:Receptors, Transferrin / Q000097:blood*; D014168:Transferrin / Q000032:analysis*; D014481:United States
chemical_list: D011990:Receptors, Transferrin; D014168:Transferrin; D007501:Iron