A system (10; 100) for preparing a cytological specimen from a patient sample held a sample container (14; 112), the system comprising: a specimen transfer device (18; 140) including an elongate sample collector (18; 154) extending therefrom, wherein the transfer device (18; 140) is configured to position a distal end portion of the sample collector (18; 154) within the sample container (14; 112); and a membrane carried on the distal end portion of the elongated sample collector (18; 54); characterized in that the system (10;100) further comprises: a pressure tank (30; 142, 144) having an output fluidly coupled to the specimen transfer device (18; 140) and configured for communicating at least one of positive pressure and vacuum pressure through the specimen transfer device (18; 140); a temperature adjusting unit (34; 146, 148, 164, 174, 194) thermally coupled to the pressure tank (30; 142, 144), and a controller (32; 163, 174, 193) operatively coupled to the temperature adjusting unit (34; 146, 148, 164, 174, 194), wherein the controller (32; 163, 174, 193) is configured for causing the temperature adjusting unit (34; 146, 148, 164, 174, 194) to incrementally adjust a pressure in the pressure tank (30; 142, 144) to within a desired pressure range as measured by a pressure sensor by heating or cooling a wall of the pressure tank (30; 142, 144), such that a sample is collected on the membrane by communicating a positive or negative pressure from the pressure tank (10; 142, 144) through the elongate sample collector (18; 154). a specimen transfer device (18; 140) including an elongate sample collector (18; 154) extending therefrom, wherein the transfer device (18; 140) is configured to position a distal end portion of the sample collector (18; 154) within the sample container (14; 112); and a membrane carried on the distal end portion of the elongated sample collector (18; 54); characterized in that the system (10;100) further comprises: a pressure tank (30; 142, 144) having an output fluidly coupled to the specimen transfer device (18; 140) and configured for communicating at least one of positive pressure and vacuum pressure through the specimen transfer device (18; 140); a temperature adjusting unit (34; 146, 148, 164, 174, 194) thermally coupled to the pressure tank (30; 142, 144), and a controller (32; 163, 174, 193) operatively coupled to the temperature adjusting unit (34; 146, 148, 164, 174, 194), wherein the controller (32; 163, 174, 193) is configured for causing the temperature adjusting unit (34; 146, 148, 164, 174, 194) to incrementally adjust a pressure in the pressure tank (30; 142, 144) to within a desired pressure range as measured by a pressure sensor by heating or cooling a wall of the pressure tank (30; 142, 144), such that a sample is collected on the membrane by communicating a positive or negative pressure from the pressure tank (10; 142, 144) through the elongate sample collector (18; 154). a pressure tank (30; 142, 144) having an output fluidly coupled to the specimen transfer device (18; 140) and configured for communicating at least one of positive pressure and vacuum pressure through the specimen transfer device (18; 140); a temperature adjusting unit (34; 146, 148, 164, 174, 194) thermally coupled to the pressure tank (30; 142, 144), and a controller (32; 163, 174, 193) operatively coupled to the temperature adjusting unit (34; 146, 148, 164, 174, 194), wherein the controller (32; 163, 174, 193) is configured for causing the temperature adjusting unit (34; 146, 148, 164, 174, 194) to incrementally adjust a pressure in the pressure tank (30; 142, 144) to within a desired pressure range as measured by a pressure sensor by heating or cooling a wall of the pressure tank (30; 142, 144), such that a sample is collected on the membrane by communicating a positive or negative pressure from the pressure tank (10; 142, 144) through the elongate sample collector (18; 154).