| abstract |
An apparatus for automatically performing analytical testing of individual distant samples of biological fluids wherein a test sample is reacted with test reagents and tested for a change in optical characteristics. A memory stores a plurality of different test protocols. An operator-actuated keyboard is used to select one of the test protocols from the memory. Individual distinct samples of biological fluid to be tested are received in a sample cell. The cell is heated to a preselected temperature. The apparatus transports an individual sample cell to a first location adapted to filter unwanted nonfluid material from the fluid to be tested and to remove excess fluid to be tested from the sample cell to cause a precise accurate volume of fluid to remain in the sample cell for testing. After filtering and removal of excess fluid, the apparatus transports the individual sample cell from the first location to a second location for introducing a first reagent into the sample, and then transports the sample cell from the second location to a test location where a second reagent is introduced into the sample. An optical detector at the test location optically scans the sample in a vertical direction to detect a change in an optical characteristic of the sample. The apparatus provides an alphanumeric indication that a change in the optical characteristic in the sample has been detected. The invention includes a uniquely configured sample cell for receiving the samples of fluid to be tested and unique apparatus for delivering precise volumes of a liquid reagent. A liquid reservoir is pressurized with gas to a preselected pressure and is automatically regulated to maintain the pressure at a constant value. A valve in conjunction with a nozzle and a conduit adapted to impart a constant flow rate to reagent being delivered is opened for precise, predetermined time intervals so that a precise predetermined volume of liquid flows through the valve in the predetermined time interval. |