MODEL RELEASED. Blood testing. Medical laboratory worker using a blood gas analyser to analyse a blood sample (in tube at lower centre). This blood gas analyser is the Rapidlab 845 from Bayer Diagnostics. This can determine levels of oxygen, carbon dioxide, the blood pH, and also levels of ions such as sodium, potassium, calcium and chloride. It can also measure blood sugar levels and the amount of haemoglobin in the blood. Automated machines, such as this one, allow rapid testing of blood samples, increasing efficiency and minimising errors. The Rapidlab series was launched in 1994.