The present study correlated histopathology and diagnostic tests in hemodialysis patients with serologic markers for hepatitis C virus (HCV). Hepatitis C virus infection was found in 65 of 163 patients, as assessed by anti-c100-3 (ELISA 1), anti-c22-3, c33C (ELISA 2), and RIBA 2. Several histopathologic patterns were found in 33 liver samples from HCV-positive individuals: cirrhosis (n = 3), chronic active hepatitis (n = 14), chronic persistent hepatitis (n = 2), isolated hemosiderosis (n = 5), reactive hepatitis (n = 6), and others (n = 3). There was a positive correlation between time from the first aminotransferase peak and histologic damage (P = 0.015). However, the severity of liver disease did not correlate with the intensity of RIBA 2 positivity, mean levels or pattern of aminotransferases elevation, or markers of past hepatitis B virus infection. Moreover, aminotransferases were persistently normal in three patients with severe liver disease and were elevated in 10 patients with only mild changes. In 19 biopsied patients, the presence of plasma HCV RNA was examined by the polymerase chain reaction (PCR), which was positive in 15 of the 19 biopsy specimens. The ability of PCR positivity to predict the histologic severity of the disease was insufficient: four patients with minor liver damage had positive PCR and two patients with significant liver damage had negative PCR. No further correlations of PCR positivity were found with the other biochemical or immunologic markers of HCV infection.(ABSTRACT TRUNCATED AT 250 WORDS)