Some individuals who must use pulse oximeters may be under the mistaken impression that these devices record certain aspects of a person's blood that the machine is actually incapable of measuring. For example, while a pulse oximeter will measure the oxygenation of a person's blood, the device is not capable of providing results that show how well that oxygenated blood is being utilized by the person. The device is also incapable of providing results on the metabolism of oxygen in the blood. The measuring of oxygenation in the blood is also a process easily marred by the addition of supplemental oxygen.