title: Distribution of transferrin saturation in an Australian population: relevance to the early diagnosis of hemochromatosis.
abstract: OBJECTIVE
  An elevated transferrin saturation is the earliest phenotypic abnormality in hereditary hemochromatosis. Determination of transferrin saturation remains the most useful noninvasive screening test for affected individuals, but there is debate as to the appropriate screening level. The aims of this study were to estimate the mean transferrin saturation in hemochromatosis heterozygotes and normal individuals and to evaluate potential transferrin saturation screening levels.
  
  
  METHODS
  Statistical mixture modeling was applied to data from a survey of asymptomatic Australians to estimate the mean transferrin saturation in hemochromatosis heterozygotes and normal individuals. To evaluate potential transferrin saturation screening levels, modeling results were compared with data from identified hemochromatosis heterozygotes and homozygotes.
  
  
  RESULTS
  After removal of hemochromatosis homozygotes, two populations of transferrin saturation were identified in asymptomatic Australians (P < 0.01). In men, 88.2% of the truncated sample had a lower mean transferrin saturation of 24.1%, whereas 11.8% had an increased mean transferrin saturation of 37.3%. Similar results were found in women. A transferrin saturation threshold of 45% identified 98% of homozygotes without misidentifying any normal individuals.
  
  
  CONCLUSIONS
  The results confirm that hemochromatosis heterozygotes form a distinct transferrin saturation subpopulation and support the use of transferrin saturation as an inexpensive screening test for hemochromatosis. In practice, a fasting transferrin saturation of > or = 45% identifies virtually all affected homozygous subjects without necessitating further investigation of unaffected normal individuals.
authors.affiliation: Department of Mathematics, Moorhead State University, Minnesota, USA.
authors.forename: C E
authors.initials: CE
authors.lastname: McLaren
authors.forename: G J
authors.initials: GJ
authors.lastname: McLachlan
authors.forename: J W
authors.initials: JW
authors.lastname: Halliday
authors.forename: S I
authors.initials: SI
authors.lastname: Webb
authors.forename: B A
authors.initials: BA
authors.lastname: Leggett
authors.forename: E C
authors.initials: EC
authors.lastname: Jazwinska
authors.forename: D H
authors.initials: DH
authors.lastname: Crawford
authors.forename: V R
authors.initials: VR
authors.lastname: Gordeuk
authors.forename: G D
authors.initials: GD
authors.lastname: McLaren
authors.forename: L W
authors.initials: LW
authors.lastname: Powell
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006432:Hemochromatosis / Q000175:diagnosis* / Q000235:genetics; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D014168:Transferrin / Q000378:metabolism*
chemical_list: D014168:Transferrin