A system comprising: a rack adapted to receive at least one sample container containing a preliminary sample; a fluidics system comprising at least one each of a fluidics head and pipetting apparatus, the fluidics system being adapted for movement relative to the sample container wherein the fluidics system is further configured for performing adding a diluent to the sample container and removing at least a portion of the preliminary sample from the sample container; a sensor device configured for measuring a concentration of particles in the preliminary sample and communicating the concentration; and a controller device in signal communication with the fluidics system and the sensor device; the controller device adapted to receive the measured concentration of particles in the preliminary sample from the sensor device; the controller device being further adapted to determine an amount of diluent to be added to the sample container and being further adapted to control the fluidics system to add the determined amount of diluent to the sample container characterized in that the pipetting apparatus has one or more sensor tips configured for measuring a volume of the preliminary sample and the prepared sample to determine whether the sample has the selected volume; the controller device being further adapted to determine an amount of the preliminary sample to be removed from the sample container by the fluidics system to prepare a sample having a selected concentration of particles; and the controller device being further adapted to control the fluidics system to remove the determined amount of the preliminary sample from the sample container so as to prepare the sample having the selected concentration of particles. a rack adapted to receive at least one sample container containing a preliminary sample; a fluidics system comprising at least one each of a fluidics head and pipetting apparatus, the fluidics system being adapted for movement relative to the sample container wherein the fluidics system is further configured for performing adding a diluent to the sample container and removing at least a portion of the preliminary sample from the sample container; a sensor device configured for measuring a concentration of particles in the preliminary sample and communicating the concentration; and a controller device in signal communication with the fluidics system and the sensor device; the controller device adapted to receive the measured concentration of particles in the preliminary sample from the sensor device; the controller device being further adapted to determine an amount of diluent to be added to the sample container and being further adapted to control the fluidics system to add the determined amount of diluent to the sample container characterized in that the pipetting apparatus has one or more sensor tips configured for measuring a volume of the preliminary sample and the prepared sample to determine whether the sample has the selected volume; the controller device being further adapted to determine an amount of the preliminary sample to be removed from the sample container by the fluidics system to prepare a sample having a selected concentration of particles; and the controller device being further adapted to control the fluidics system to remove the determined amount of the preliminary sample from the sample container so as to prepare the sample having the selected concentration of particles.