To prevent bacterial contamination of blood transfusion media, the following three types of rooms in blood service institutions should meet especially high requirements for cleanness: 1. Box and its foreroom (or room equipped with laminar cabinet) for open-air preparation of washed red blood cells or other blood components. 2. Box (laminar cabinet) in bacteriological laboratory. 3. Two areas of gene diagnosis laboratory: a) for RNA detection (HIV and HCV diagnosis) to prevent sample contamination with extraneous RNAases; b) for preparation of in-house test kits. Required cleanness of rooms in blood service institutions can be attained using the following equipment available from Laminarnye Sistemy, Ltd. (Miass, Chelyabinsk Region, Russia): clean chamber equipment; abacterial air environment box for working with agents and microorganisms; box for working with DNA samples.