Specimen processing systems, pipette assemblies and methods for preparing reagents

A reagent pipette for an automated slide processing apparatus configured to dispense liquids onto one or more microscope slides, the reagent pipette comprising:

• a proximal end portion configured to couple with a body of a reagent pipette assembly and a distal end portion opposite the proximal end portion, the proximal end portion including a proximal opening;
• and
• a tubular main body extending between the proximal and distal end portions and including a flat radially outwardly facing external surface portion positioned at the distal end portion of the reagent pipette and configured to circumferentially orient the regent pipette within a retainer when the reagent pipette is inserted into the retainer and the retainer is in a first configuration for engaging a rotation inhibitor and securing the reagent pipette to the reagent pipette assembly, and the retainer releases the reagent pipette by disengaging the rotation inhibitor when the retainer is a second configuration, wherein the flat radially outwardly facing external surface is configured to inhibit rotation of reagent pipette with respect to the retainer by being engaged by the rotation inhibitor of the retainer when the retainer is in the first configuration, wherein the reagent pipette is configured to be movable by the automated slide processing apparatus between at least one loading position for obtaining reagent from a reagent container at a filling station when a vacuum is applied via the proximal opening and at least one dispense position for dispensing the obtained reagent.