The level of assurance in sterilization or the abbreviation SAL in microbiology to describe the probability of stay a unit(whether by the piece or material) after the process of sterilization, and sterilization. Manufacturers of medical equipment, design processes, sterilization to very low levels(one in a million) stay defined and standardized. In other words, in the definition of this coefficient, a is a hypothetical, so planning to be that as long as it should be from any one megabit undergo the process of sterilization is only a bit non-sterile stay.

attention to this point, it is essential that Microbiology is impossible to prove that all microorganisms is discovered, have been destroyed, because, firstly, may be undetectable cuddly only because this is the moment of Test in the appropriate environment, activities, understanding, and the Duma may include microorganisms is discovered, not discovered. so in these conditions, the coefficient of contingency SAL (or probability stay a bit) can be used.