MIC is the lowest concentration of an antibacterial agent expressed in mg/ml (µg/ml) which, under strictly controlled in vitro conditions, completely prevents visible growth of the test strain of an organism. The knowledge of MIC is essential for the clinicians in order to determine the correct antibiotic concentration for treating infections cause by certain bacterial species. In case of seriously ill-patients, who suffer from chronic infections and have been treated with broad spectrum of antibiotics and have a history of failed therapies, much more precise effective dosage of antibiotic is required. Among other parameters, MIC is an important one. It has significant impact on the choice of a therapeutic strategy.

The usage of the proper dose is also required to reduce the potential side effects that is experienced by the patients. MIC is one of the best ways to prevent antibiotic resistance from developing across bacterial species. The genetically inherited ability of bacteria to resist the inhibitory effects of an antibiotic is known as antibiotic resistance. Instead of growth inhibition, bacteria continue to multiply when they antibiotic resistant. This phenomenon develops when too high of an antibiotic dose is prescribed to a patient, or when the infection is not caused by bacteria and an antibiotic is prescribed to the patient.

There are several methods to determine MIC of an antibiotic. These methods includes:

1. Broth dilution method
2. Antimicrobial gradient method
3. Disk diffusion test