In this paper an attempt has been made at quantitative evaluation of reactivity of various types anti-HCV using proposed BLOT-index. We based our research on 20 patients diagnosed with hepatitis-C (clinical, biochemical, serological and enzymatical criteria--repeatedly positive results of second generation screening tests EIA ABBOTT HCV and UBI HCV Monoelisa Organon Teknika) who were anti-HCV determined at the beginning the acute phase and after 3 and 6 months. Multiantigen tests were used veryfying LIATEK-HCV 2 and LIATEK-HCV 3 Organon Teknika. Value of BLOT-index was algebraic sum of "pluses" for particular anti-HCV. Three models of dynamics of BLOT-index were observed: increase, plateau and decrease. Statistically significant differences between values of BLOT-index were shown at the beginning of the acute phase of hepatitis-C and after 6 months. There were no differences observed between convalescents and patients who developed chronic hepatitis-C (test t-Student's and f-Fisher's). Reactivity of anti-HCV, evaluated using BLOT-index, shown increasing trend, which is a dominant pattern, however quantitative and qualitative changes do not occur more frequently than every 6 months. The LIATEK-HCV 3 gives fewer undetermined reactions and detects anti-HCV earlier than a former generation of this test.