Abstract: Fluid sample tester assembly (12) comprises a cartridge (6) having a pressure chamber (22) and entrance port (20) connected by a passageway (24). An analyte reagent (36) is positioned along the fluid passageway so that when a liquid sample (28) is drawn through the entrance port into the passageway, the analyte reagent mixes with the sample. The sample is preferably drawn into the cartridge by temporarily reducing the volume of the pressure chamber, applying the sample to the entrance port and then returning the pressure chamber to its initial volume; this can also be done by heating the chamber, contacting the sample and then cooling the chamber. The end of the sample defines a boundary surface (30) along the fluid passageway. Positive and negative pressure is applied to the sample to cause the boundary surface to oscillate within the passageway.

Abstract: A sample collection and manipulation apparatus (2), typically used for collecting and manipulating a blood sample and measuring a component of that sample with the use of a reagent or ion-selective electrodes, includes a body member (4, 6, 8) defining a thermal pressure chamber (22) and a sample port (10). A measurement chamber (26) is formed along a fluid passageway (42, 16, 24) connecting the thermal pressure chamber with the sample port. The air within the thermal pressure chamber is preheated (54, 56, 60, 62, 63/65) to reduce its density and the sample port is then placed in contact with the liquid. As the gas cools, a partial vacuum is created within the thermal pressure chamber to draw a liquid sample through the passageway and into the measurement chamber. Appropriate analyte measurement techniques, such as optical or electrochemical, can then be carried out. Applications include the testing of blood gases, glucose, hemoglobin, electrolytes, coagulation and therapeutic drugs.