Method of washing a fluidic system of an in-vitro diagnostic analyzer

An automated method of washing a fluidic system of an in-vitro diagnostic (IVD) analyzer from a previous fluid, the fluidic system comprising at least one fluidic path, the IVD analyzer further comprising at least one fluid-selection valve for selecting between fluids including a wash fluid and air, a pump and a controller configured to operate according to either a time-priority mode or a wash-fluid-priority mode, the method comprising controlling by the controller the pump and the at least one fluid-selection valve for pumping the wash fluid and/or air through the at least one fluidic path, wherein in the time-priority mode the method comprises pumping air at a first speed, in a first step, in order to remove the previous fluid from the at least one fluidic path, and pumping wash-fluid plugs alternated to air plugs such that consecutive wash-fluid plugs are separated by an air plug, in a second step, in order to wash out residuals of the previous fluid, and wherein in the wash-fluid-priority mode the controller is configured to operate according to either a sample-wash mode if the previous fluid is a sample or according to an other-fluid-wash mode if the previous fluid is any fluid other than a sample, wherein in the sample-wash mode the method comprises pumping air at a lower speed than the first speed, in a first step, in order to remove the previous fluid from the at least one fluidic path, pumping at least one wash-fluid plug at higher speed than the lower speed, in a second step, and pumping wash-fluid plugs alternated to air plugs such that the consecutive wash-fluid plugs are separated by the air plug at the lower speed, in a third step, in order to wash out residuals of the previous fluid, and wherein in the other-fluid-wash mode the method comprises pumping air at the lower speed, in a first step, in order to remove the previous fluid from the at least one fluidic path and pumping wash-fluid plugs alternated to air plugs such that the consecutive wash-fluid plugs are separated by the air plug at the lower speed, in a second step, in order to wash out residuals of the previous fluid.