Accuracy of b-GGT fraction for the diagnosis of non-alcoholic fatty liver disease
Article first published online: 3 NOV 2011
© 2011 John Wiley & Sons A/S
Volume 32, Issue 4, pages 629–634, April 2012
How to Cite
Franzini, M., Fornaciari, I., Fierabracci, V., Elawadi, H. A., Bolognesi, V., Maltinti, S., Ricchiuti, A., De Bortoli, N., Marchi, S., Pompella, A., Passino, C., Emdin, M. and Paolicchi, A. (2012), Accuracy of b-GGT fraction for the diagnosis of non-alcoholic fatty liver disease. Liver International, 32: 629–634. doi: 10.1111/j.1478-3231.2011.02673.x
- Issue published online: 8 MAR 2012
- Article first published online: 3 NOV 2011
- Manuscript Accepted: 3 OCT 2011
- Manuscript Received: 21 JUL 2011
- G. Monasterio Foundation CNR-Regione Toscana
- chronic viral hepatitis C;
- gamma-glutamyltransferase fractions;
- non-alcoholic fatty liver disease
Serum gamma-glutamyltransferase (GGT) activity is a sensitive but non-specific marker of non-alcoholic fatty liver disease (NAFLD). Recently, four GGT fractions (big-, medium-, small-, free-GGT) were described in humans.
We aimed to investigate whether a specific GGT fraction pattern is associated with NAFLD.
Gamma-glutamyltransferase fractions were determined in patients with NAFLD (n = 90), and compared with those in control subjects (n = 70), and chronic hepatitis C (CHC, n = 45) age and gender matched.
Total GGT was elevated in NAFLD as compared to controls (median, 25°–75°percentile: 39.4, 20.0–82.0 U/L vs. 18.4, 13.2–24.9 U/L respectively, P < 0.001). All fractions were higher in NAFLD than in controls (P < 0.001). The b-GGT showed the highest diagnostic accuracy for NAFLD diagnosis [area under ROC curve (ROC-AUC): 0.85; cut-off 2.6 U/L, sensitivity 74%, specificity 81%].
Also subjects with CHC showed increased GGT (41.5, 21.9–84.5 U/L, P < 0.001 vs. controls, P = n.s. vs. NAFLD), as well as m-, s-, and f-GGT, while b-GGT did not show any significant increase (P = n.s. vs. HS, P < 0.001 vs. NAFLD). In subjects with CHC, s-GGT showed the best diagnostic value (ROC-AUC: 0.853; cut-off 14.1 U/L, sensitivity 73%, specificity 90%). Serum GGT did not show any value in the differential diagnosis between NAFLD and CHC (ROC-AUC 0.507, P = n.s.), while b-GGT/s-GGT ratio showed the highest diagnostic accuracy for distinguishing NAFLD and CHC (ROC-AUC: 0.93; cut-off value 0.16, sensitivity 82%, specificity 90%).
b-GGT increases in NAFLD, but not in CHC. GGT fraction analysis might help in improving the sensitivity and specificity of the diagnosis of NAFLD and other liver dysfunctions.