Feb. 22, 2021 -- Pulse oximeters, which measure blood oxygen levels, have become popular during the COVID-19 pandemic for people to track their oxygen saturation, but they may not always be accurate, the FDA cautioned in new guidance released Friday.
Several factors can affect the accuracy of pulse oximeters, including poor circulation, skin temperature, skin thickness, current tobacco use, use of fingernail polish, and dark skin pigmentation, the FDA said. Recent reports have found that Black patients may not receive accurate readings from some oximeters.
“While pulse oximeters may be useful for estimating blood oxygen levels, these devices have limitations that can result in inaccurate readings,” William Maisel, MD, director of the FDA’s Office of Product Evaluation and Quality, said in a statement.
Maisel encouraged people to pay attention to all of their health symptoms, especially if they experience signs of low oxygen saturation levels, such as shortness of breath or bluish coloring on their face, lips, or nails.
“Patients with conditions such as COVID-19 should not rely solely on pulse oximeter measurements to monitor their health at home as they are not a substitute for a medical diagnosis by a health care provider,” he said.
A pulse oximeter, which is typically placed on the fingertip, uses infrared light beams to estimate the amount of oxygen in the blood and the pulse rate. Typical oxygen saturation levels vary between 95% to 100% and can be somewhat lower in people with lung problems. Health care providers and consumers have monitored oxygen saturation during the pandemic because COVID-19 can cause levels to drop, with lower than 90% being a cause for concern.
Consumers can buy over-the-counter oximeters in stores or online, but they’re not intended for medical use and don’t undergo FDA review, according to the FDA alert. Prescription oximeters undergo FDA review and are typically used in hospitals and doctor’s offices, though sometimes patients receive a prescription to use one at home.
The FDA guidance gives tips to help patients and caregivers take an accurate reading and interpret the results correctly. Importantly, changes or trends in measurements are more meaningful than a single measurement, according to the guidance. If patients are concerned about a pulse oximeter reading, they should contact their healthcare provider, especially if their symptoms become worse or they think they may have COVID-19.
The FDA is evaluating the current research about pulse oximeter accuracy, particularly with a focus on studies that evaluate whether the products are less accurate for people with darker skin. Based on new findings, the FDA may update its pulse oximetry guidance and will inform the public if new information becomes available. The FDA also encourages consumers to report any pulse oximeter issues through the MedWatch Voluntary Reporting Form.