The MS-2 instrumented system using automatic processes, performs antibiotic susceptibility tests turbidimetrically. MS-2 uses densitometric measurements to determine growth or inhibition of growth in bacterial cultures in antibiotic susceptibility tests. MS-2 uses a sensitive photometer that measures turbidity to determine susceptibility or resistance. Growth of bacteria from a specimen can be detected by MS-2 by an increase in turbidity and enumeration can be performed as an increase in turbidity is directly related to the bacterial population. The MS-2 is a modular instrumented system performing automated processes designed to determine antibiotic susceptibilities and minimum inhibitory concentrations (MICs) by kinetic analysis of microbial growth using the principle of turbidimetric assay. MS-2 routinely provides MIC for more meaningful guidance in treatment. There is increasing recognition that MICs offer more information as a treatment guide than qualitative susceptibility values, and the MS-2 offers MIC values routinely.