For determining the type of causal agent of infectious diseases and for checking their sensitivity to antibiotics and chemotherapeutic agents in vitro by means of the inhibition zone determination method. The antibiogram allows rational and selective chemotherapy. The test discs can be coated with chemotherapeutic agents placed on the inoculated nutrient agar and incubated.- Antibiotic Assay Paper, 9mm Discs, 1000/pk