Surviving COVID-19: The most important test may be at your fingertips

Surviving COVID-19: The most important test may be at your fingertips
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Widespread tracking of non-symptomatic COVID-19 infections is critical for epidemiologists. It factors into crucial public policy decisions regarding the reopening of the economy and the potential spread of infection. As an emergency physician, I have a singular mission: Treat urgent and emergent medical problems; intervene in disease and prevent death; identify patients who need to come into the hospital versus those who can safely be sent home.

With COVID-19, one of the best tools we’ve found is literally at the tips of our fingers: pulse oximetry. This small device placed on a finger for 15 seconds to measure heart rate and oxygen levels in the blood could help us win the war on COVID-19. Widespread use of this simple testing has the potential to transform care, ease the strain on health care resources, and save lives. 

In every area of medicine and every disease process, earlier diagnosis and treatment is best. There is an intervention window for almost all diseases, a period during which a diagnosis can be made and treatment initiated. The goal in every case is to prevent disease-related injury and death. COVID-19 is no different.


While we have no cure yet, treating COVID-19 pneumonia with oxygen, positioning maneuvers that open up areas of the lung (having patients lay on their stomachs) and managing the associated inflammation can significantly lower the need for mechanical ventilation and related complications. These interventions work best before patients become seriously ill.

Pulse oximetry is our earliest, most valuable biomarker of illness in COVID-19 because of how this virus causes progressive lung injury without patients realizing it. Most patients do not feel shortness of breath, chest pain, or have a regular recurrent fever and do not realize they are becoming life-threateningly ill. This “silent hypoxia,” or low oxygen, progresses over three to five days; patients typically present with advanced pneumonia five to 10 days after the initial infection. 

Clinicians, medical directors and patients need to think about pulse oximetry monitoring in COVID-19 the way we do biomarkers for heart attacks. In the same way, elevated levels of troponin in the blood are a reliable indicator of heart damage. Patients and clinicians cannot exclude early lung infection in COVID-19 without pulse oximetry.

What if a patient tests positive with a nasal swab for COVID-19? As an ER doctor, I would do nothing immediately if their oxygen saturation and other vital signs are reasonable. They are not symptomatic — except to recommend that they are monitored with pulse oximetry to help detect COVID-19 pneumonia before they get critically ill. 

Pulse oximetry is already available in nearly every nursing and health care facility and every ambulance. It is an inexpensive, generally reliable technology that is easier to use than a thermometer or a blood pressure cuff. Until an effective vaccine becomes commonplace, we are dealing with a respiratory pandemic. A pulse oximeter should become something in every household medicine cabinet. It also the most valuable instrument a patient can use with a telehealth provider to determine the need for going to the hospital.


It is essential to realize that COVID-19 often is a family affair. We are telling people who test positive to self-isolate, yet, if they stay in their homes, this usually means infecting their loved ones. I have seen husbands and wives suffer severe pneumonia requiring simultaneous hospitalization, and cases where family members showing symptoms within days of a loved one dying or requiring a ventilator. 

In the ER, we know that when one occupant dies in a car crash, there is a higher risk of injury in all other occupants. We should think the same way about COVID-19: When one family member is positive, other family members are at high risk — and, in patients who suffer a critical illness, family members should be evaluated and monitored with pulse oximetry. Even if family members test negative but have viral symptoms, I still advocate for pulse oximetry monitoring. Our swab testing is far from perfect and a false negative could be very dangerous. 

As our nation expands testing, what should we do following a positive test? Ferrari, the Italian automaker, has set a high standard: Workers returning to its production lines are fever-checked, swab-tested and antibody-tested. If a worker tests positive, their entire family is checked and provided an apartment, for the employee to be monitored with a pulse oximeter for two weeks. 

It is heartening to see the rapid advancements in research and development, and that we are expanding testing and beginning to marshal the resources needed to face this pandemic. But we must do more than a test. If we do not add monitoring, this disease will continue to kill silently, lead to presentations of advanced pneumonia, and cause huge resource demands on our health system. We must add pulse oximetry monitoring to those who test positive and in high-risk populations where COVID-19 already is documented.

We will not win this prolonged war without changing the rules of engagement through earlier diagnosis and earlier treatment, no matter how much testing we do. Silent hypoxia kills — and pulse oximetry is the best way to detect it.

Richard M. Levitan, M.D., practices emergency medicine at Littleton (N.H.) Regional Hospital. He invented the Airway Cam, an imaging system to teach the proper intubation of patients and other airway devices. He is president of Airway Cam Technologies, which runs courses on emergency airway management.