The development of medical devices for diagnostics is one of the greatest challenges in the biomedical industry. A significant revolution in diagnostics occurred with the development of medical devices designed to be used outside the clinical laboratory and in close proximity to where the patient is receiving care. These instruments belong to the family of Point of Care systems and play a key role in many circumstances being crucial in clinical care settings and emergencies. This thesis will focus on the cobas b 123 Point of Care system, a cartridge based mobile blood gas and electrolytes analyser designed for critical point of care testing.