What does a Pulse Oximeter Do? and Do you need one?

A Finger Tip Pulse Oximeter like the one sold on the BIOS Medical website measures blood oxygen saturation or SpO2.  The device uses two frequencies of light (red and infrared) to determine the % of hemoglobin in the blood. (Oxygen binds to hemoglobin in red blood cells in our lungs and then is pumped throughout the body). Light Emitting Diodes project through the finger and the hemoglobin absorbs different amounts of the light depending on the amount of oxygen present.  The normal range for a healthy person is 95% - 100% SpO2. 

These products are simple to use by inserting your finger.  The accuracy can be affected by poor circulation or the presence of finger nail polish or false finger nails. Used properly, BIOS oximeters have an accuracy of +2% and also display pulse rate in beats per minute.  Most pulse oximeters are used by people with sustained levels of SpO2 below 93%, and frequently require supplemental oxygen. 

Covid 19 is a respiratory tract infection that the entire world is being exposed to.  Although most people can deal with the disease on their own without hospitalization, about 5% develop “acute respiratory distress syndrome” (ARDS) and possibly other complications including sepsis, and septic shock, multi-organ failure including cardiac and kidney injury. People with these conditions will require critical care and will likely be treated with supplemental oxygen.(1)

While 81% of people will experience an uncomplicated upper respiratory tract infection accompanied by fever, fatigue, cough (with or without sputum), muscle pain, sore throat, head ache etc.(2) It sounds like  bad cold or Flu symptoms, right?  Therefore, the vast majority of people won’t really benefit from a pulse oximeter, their SpO2 levels won’t drop to < 93%, breathing normal air.

However, approximately 14% of people with Covid 19 may develop pneumonia.  Pneumonia symptoms include: fever, high pulse rate, crackly breath sounds and lower oxygen levels. This condition can progress to severe pneumonia with SpO2 <93% and respiration rates > 30 breaths per minute.  This group should ultimately be treated in hospital.  If this progresses to ARDS, the patient will be treated in ICU.  It is unlikely that normal healthy people will need a pulse oximeter even if they get Covid 19, but individuals with compromised immune systems and those with pre-existing conditions like Chronic Obstructive Pulmonary Disease (COPD) who are already on supplemental oxygen will benefit from a Finger Tip Pulse Oximeter. 

Author: Mark Beaton, Sr. VP of Marketing, BIOS Medical


  1. Clinical Management of Severe Acute Respiratory Infection with COVID-19 Disease - Mar 13, 2020. World Health Organization  
  1. World Health Organization Library 2011 Pulse Oximetry Training Manual


Leave a comment

Please note, comments must be approved before they are published.