ABSTRACT: Feigelson, J., Pecau, Y., Cathelineau, L. and Navarro, J. (49, Bd Bessieres 75-Paris XVIIO, France). Additional data on hepatic function tests in cystic fibrosis. Acta Paediatr Scand 64:337, 1975.–Fifty cystic fibrosis (CF) patients, of whom 9 had multilobular cirrhosis, were observed regularly for a period of 3 years and various liver function tests, indicating cytolysis, cholestasis and cellular insufficiency were performed. Immunoglobulin and prothrombin were assayed. In 9 patients with cirrhosis, the tests were generally abnormal. Two distinct biochemical patterns of cirrhosis were distinguished, one clearly cholestatic and the other of a more cellular type. The distinction was made on the basis of the IgA: Transferrin ratio and of gamma-glutamyl-transpeptidase levels. In the non-cirrhotic patients, a temporary increase of cytolysis and cholestasis was observed in 50 % of the cases.