There are only two ways to check the oxygen levels in your blood: an arterial blood gas and pulse oximetry. Before we discuss what a pulse oximeter is, let’s briefly cover how arterial blood gases relate to pulse oximetry.
The gold standard for checking oxygen levels in your blood is by drawing an arterial blood gas, which is blood from your artery. This blood test provides accurate data regarding other substances in your blood including carbon dioxide and bicarbonate. However, since this test involves a needle stick, routine testing is usually uncomfortable for patients and generally more expensive.
The pulse oximeter was created as a noninvasive alternative to arterial blood gas sampling and provides accurate estimates of oxygen saturation without the need to draw blood. Oxygen saturation is a number that shows you how saturated your blood is with oxygen, expressed as a percent. This device simply rests on your fingertip and measures your oxygen level using a painless red light.
Within seconds, a pulse oximeter can tell you how saturated your blood is with oxygen
and will also show your heart rate. In healthy individuals, normal oxygen saturation levels are 97%–100%, although many illnesses may cause this number to drop below 96%. Pulse oximeters have become a critical tool to quickly assess oxygen levels in the hospital setting and even at home.
If you are using oxygen at home, it is highly recommended that you have a portable pulse oximeter handy. This device will give you an accurate number you can use to assess your oxygen level at any given time.