Introduction:
The combined therapy of pegylated alpha interferon and rybavirin is a gold standard of chronic viral hepatitis C (cvhC) treatment.

Aim:
The aim of the study is to evaluate the laboratory test differences between the group of cvhC patients which achieved and did not achieve sustained virologic response (SVR).

Materials and methods:
51 patients (25 women, 26 men, age 48.7 ± 12.8 years) were divided into two groups depending on SVR achievement. SVR was achieved in 41.2% of patients [(SVR(+)]. The concentration of hemoglobin, hematocrite, the number of erythrocytes, leucocytes, platelets, glucose, bilirubin, creatinin, uric acid, fT3, fT4, TSH, C-reactive protein (CRP), the activity of asparaginian and alaninian transaminases, alkaline phosphatase, gammaglutamylotranspeptidase, were estimated before the start of treatment and after 12, 24, 48 and 72 weeks after beginning it. Statistic analysis was performed by ANOVA of Friedmann, U Mann-Withney and t-Student tests.

Results:
The activity of AspAT, AlAT in the SVR(+) group was lower from the 12th week until the 72nd week of observation. GGTP activity was statistically significant lower in the SVR(+)group. The decrease in TSH concentration in the 12th week and the increase in fT4 concentration in week 24 was clearer in the SVR(+) group. The hematocrite was lower in the SVR(+) group in the 48th week from the beginning of therapy and 24 weeks after the end of it.

Conclusions:
Patients treated with pegylated interferon α2a and rybavirine due to cvhC rarely achieve SVR if the GGTP activity is higher before the treatment and if the aminotranferases activity is higher during therapy. Latent hyperthyreosis can be a good predictive factor.