Turn on the pulse oximeter and place it on your fingertip, ideally the middle or index finger. Sit still and avoid moving while the device reads your oxygen levels and heart rate. The screen will display your oxygen saturation level (SpO2) and pulse rate within seconds. Ensure the reading is stable for 30 to 60 seconds before removing the device.

When interpreting the readings of a pulse oximeter, it’s important to understand what the numbers mean. The oxygen saturation level is shown on the device as SpO2. This reflects the percentage of oxygen in your blood. A normal reading typically ranges from 95% to 100%.

Pulse output voltage can vary based on the metering equipment used. Many pulse outputs are “volt-free” or “dry contacts,” where the pulse is produced by closing a circuit without voltage. Other systems produce pulses by a voltage going high, where the pulse output involves a change in voltage level.

The most popular are portable handheld and fingertip pulse oximeters. Portable pulse oximeters can be purchased from a wide array of stores, including drugstores like Walgreens and CVS, big-box stores like Walmart, and even online. Most pulse oximeters are clip-like and look like a clothespin.