A method for dynamic dosing of disinfectant solution in a medical device reprocessing system includes calculating a volume of an initial dose of concentrated disinfectant solution for dilution to make a first in-use disinfectant solution. The initial dose of concentrated disinfectant solution is diluted with diluting fluid to make the first in-use disinfectant solution comprising a target concentration of disinfectant agent. The first in-use disinfectant solution is applied to a medical device. A concentration of the disinfectant agent in the first in-use disinfectant solution is then calculated. The actual concentration of the disinfectant agent in the concentrated disinfectant solution is then calculated based upon the concentration of disinfectant agent in the first in-use disinfectant solution. It is then determined whether a volume of a second dose of concentrated disinfectant solution is increased or about the same as the volume of the initial dose to make a second in-use disinfectant solution.
