This Instruction establishes the methods by which cattle blood serum shall be controlled for the presence of extraneous viruses and mycoplasms. Cattle blood serum is widely used for the manufacturing of prophylactic and diagnostic immunobiological preparations and for the cultivation of cell cultures. Cattle blood serum control consists of two methods: (a) microbiological method based upon a diagnosis of mycoplasm growth after the introduction of serum under test into growth medium with a diagno