Pulse oximeters, which simply clip onto your fingertip, are non-invasive devices that can measure blood oxygen saturation as well as pulse (heart rate). They are relatively inexpensive (about $20) and can be purchased for home ("non-medical") use.
Although they are not as accurate as FDA-approved "medical" pulse oximeters, which cost much more and undergo more rigorous testing, comparison studies indicate that some (but not all) non-medical pulse oximeters can help signal when medical attention is needed in conditions such as COVID-19, asthma, and chronic obstructive pulmonary disease (COPD).
Learn the pros and cons of non-medical pulse oximeters, which brand (available on Amazon and online) has performed best in studies, and tips on using a pulse oximeter. Sign in as a ConsumerLab member.