A system for preparing an output sample of a defined concentration, comprising: one or more fluid delivery conduits configured to dilute an aliquot of a source sample comprising an infectious agent by a dilution factor to yield a diluted sample; one or more sensors configured to be exposed to the diluted sample, wherein at least a part of each of the one or more sensors is in fluid communication with the diluted sample when exposed to the diluted sample; an incubating component configured to incubate the diluted sample at an incubation temperature, wherein the diluted sample is incubated when the one or more sensors are exposed to the diluted sample; a computing device comprising one or more processors, wherein the computing device is communicatively coupled to the one or more sensors, characterized in that the one or more processors are programmed to: select a first threshold amount and a second threshold amount from a look-up table, wherein the first threshold amount and the second threshold amount represent changes in a solution characteristic of the diluted sample; monitor a change in the solution characteristic of the diluted sample; obtain a first threshold time corresponding to an amount of time elapsed for the solution characteristic of the diluted sample to change by the first threshold amount and obtain a second threshold time corresponding to the amount of time elapsed for the solution characteristic of the diluted sample to change by the second threshold amount; and determine a sample preparation time corresponding to the amount of time necessary for the infectious agent within the diluted sample to reach the defined concentration based on the first threshold time, the second threshold time, concentration data from the look-up table, and the defined concentration. one or more fluid delivery conduits configured to dilute an aliquot of a source sample comprising an infectious agent by a dilution factor to yield a diluted sample; one or more sensors configured to be exposed to the diluted sample, wherein at least a part of each of the one or more sensors is in fluid communication with the diluted sample when exposed to the diluted sample; an incubating component configured to incubate the diluted sample at an incubation temperature, wherein the diluted sample is incubated when the one or more sensors are exposed to the diluted sample; a computing device comprising one or more processors, wherein the computing device is communicatively coupled to the one or more sensors, characterized in that the one or more processors are programmed to: select a first threshold amount and a second threshold amount from a look-up table, wherein the first threshold amount and the second threshold amount represent changes in a solution characteristic of the diluted sample; monitor a change in the solution characteristic of the diluted sample; obtain a first threshold time corresponding to an amount of time elapsed for the solution characteristic of the diluted sample to change by the first threshold amount and obtain a second threshold time corresponding to the amount of time elapsed for the solution characteristic of the diluted sample to change by the second threshold amount; and determine a sample preparation time corresponding to the amount of time necessary for the infectious agent within the diluted sample to reach the defined concentration based on the first threshold time, the second threshold time, concentration data from the look-up table, and the defined concentration. select a first threshold amount and a second threshold amount from a look-up table, wherein the first threshold amount and the second threshold amount represent changes in a solution characteristic of the diluted sample; monitor a change in the solution characteristic of the diluted sample; obtain a first threshold time corresponding to an amount of time elapsed for the solution characteristic of the diluted sample to change by the first threshold amount and obtain a second threshold time corresponding to the amount of time elapsed for the solution characteristic of the diluted sample to change by the second threshold amount; and determine a sample preparation time corresponding to the amount of time necessary for the infectious agent within the diluted sample to reach the defined concentration based on the first threshold time, the second threshold time, concentration data from the look-up table, and the defined concentration.