How to translate a blood type used in Eastern Europe?
It is a direct correlation between the ABO blood groups and the Roman numerals. 

 O: I

 A: II

 B: III

AB: IV


This numeric system was pioneered by Jan Jansky of Czechoslovakia in the early 20th century. Apparently it is still used in some former Soviet states. 

Erb IH. 1940. Blood Group Classification (A Plea for Uniformity). Can Med Assoc J 42(5):418-421.