What does a pulse oximeter measure?

A pulse oximeter is specifically designed to measure the oxygen saturation level in the blood. This device works by attaching to a person's fingertip or earlobe, using light sensors to assess how much oxygen is being carried by the hemoglobin in red blood cells. Maintaining adequate oxygen saturation levels is crucial for ensuring that the body's organs and tissues receive the oxygen they need to function properly.

In the context of the other options, heart rate can be monitored using various methods, including a pulse oximeter, but it is not its primary function. Blood pressure requires a sphygmomanometer for accurate measurement and is not assessed by a pulse oximeter. Body temperature is typically measured with a thermometer, which also is not the capability of a pulse oximeter. Therefore, the primary and correct function of a pulse oximeter is to measure the oxygen saturation in the blood.