A pulse oximeter is a device intended for the non-invasive measurement of arterial blood oxygen saturation and pulse rate. Oximeters are used medically by patients with asthma, emphysema, chronic obstructive pulmonary disease (COPD), chronic obstructive airway diseases (COAD), and other respiratory conditions. Pilots use pulse oximeters to help guard against hypoxia. This blood oxygen tester can also help athletes, such as mountain climbers and walkers, to improve their performance. The chief advantages of pulse oximeter over other methodologies are cost and speed. The most accurate way to obtain SpO2 is from a blood sample and analyse the sample in a laboratory. An oximeter only takes a few seconds to obtain a reading. The accuracy of a pulse oximeter (usually within 1-3%) is sufficient for most saturations.