Intended use - The GEM Premier 3500 sensor and reagent PAK (cartridge) is for use by healthcare professionals to rapidly analyze heparinized whole blood samples at point of healthcare delivery (near patient test) in a clinical setting and in a central laboratory. It provides quantitative measurements of pH, pCO2, pO2 and hematocrit. These parameters, together with calculated values, support the assessment of a patient's oxygen-carrying capacity and acid-base balance.