title: Normal liver stiffness and its determinants in healthy blood donors.
abstract: BACKGROUND
  Several studies in healthy populations have investigated normal liver stiffness on transient elastography, but none has excluded subjects with fatty liver.
  
  
  OBJECTIVE
  To define normal liver stiffness and its determinants in 923 healthy voluntary blood donors with and without fatty liver.
  
  
  METHODS
  Seven hundred and forty six subjects were analyzed with transient elastography according to the absence (602) or presence of fatty liver (144) at ultrasonography. The cut-off for significant fibrosis was a liver stiffness of 7.9kPa.
  
  
  RESULTS
  Normal subjects had significantly lower liver stiffness (median 4.4kPa) than fatty liver subjects (median 5.3, p<0.001). In normal livers male gender was significantly associated with increased liver stiffness at multiple linear regression analysis. Nine (1.4%) blood donors with normal liver and 9 with fatty liver (6.2%) had >7.9kPa. Subjects with verified liver stiffness >7.9kPa, were further investigated with liver biopsy or non-invasive fibrosis markers: only 1 patient with fatty liver had >F1 fibrosis.
  
  
  CONCLUSIONS
  Liver stiffness in normal liver is lower than in fatty liver, and gender is the only influencing variable. Transient elastography has a very low false positive rate for significant fibrosis and may have a role in screening populations at risk for liver disease.
authors.affiliation: Hepatology Unit, Treviglio Hospital, Treviglio, Bergamo, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Colombo
authors.forename: Livio
authors.initials: L
authors.lastname: Belloli
authors.forename: Maurizio
authors.initials: M
authors.lastname: Zaccanelli
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Badia
authors.forename: Carlo
authors.initials: C
authors.lastname: Jamoletti
authors.forename: Marco
authors.initials: M
authors.lastname: Buonocore
authors.forename: Paolo
authors.initials: P
authors.lastname: Del Poggio
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D001782:Blood Donors; D004548:Elasticity; D054459:Elasticity Imaging Techniques; D005234:Fatty Liver / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging / Q000473:pathology / Q000502:physiology*; D008103:Liver Cirrhosis / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000473:pathology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012720:Severity of Illness Index; D012737:Sex Factors; D055815:Young Adult