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.

Aims: 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.