What is an Oximeter and how does it work?

A Pulse Oximeter is a small finger device that could be a life-saving solution for Covid patients. These gadgets offer an easy and reliable way for people to check their oxygen levels from the comfort of their home. 

Whilst this isn't a solution to stopping the spread of virus, it is vital in helping identify if someone needs hospital treatment. The NHS recommends  pulse oximeters as a simple way to monitor oxygen saturation levels while isolating at home.

How does it work?

The device reads the oxygen levels in a person's blood by emitting a light into the body. It attaches to the finger and measures how much of that light is absorbed to calculate the percentage of oxygen which is in the blood.

Normal oxygen levels in the blood are between 95 and 100 percent. Therefore, if they notice a drop to 93 or 94 percent, users should call their GP or 111.

It's advised that anyone monitoring their oxygen levels, measures and records them three times a day. Find out more.

How do I use one? 

These devices are very simple to use and can detect a low oxygen level within seconds. 

  • Make sure your hands have been washed and are now room temperature before use. 

  • Nail varnish and fake nails can disrupt the reading.

  • Put your index finger or middle finger into the device and turn it on. (Your nail must be facing upwards)

  • Keeping your hand and finger still as it takes the reading from your finger. 

  • It will display a accurately measured SpO2* and PR* number 

How are they helping people with Covid? 

The lungs can become blocked in extreme Covid cases, which prevents them from being able to transfer the oxygen you breathe into the bloodstream.

Scientists have said it still remains unclear, why oxygen levels in Covid patients' blood can drop to seriously low levels while the patient is unaware.

Whilst there isn't definite proof that the gadgets are saving lives, says Dr Inada-Kim. 

"What we think we can see are the early seeds of a reduction in the length of stay after a hospital admission, an improvement in survival and a reduction in the pressures on the emergency services," he said.

He is so convinced of their role in tackling silent hypoxia that he said everyone should consider buying one.

"Personally I would, and I know a number of colleagues who have bought pulse oximeters to distribute to their loved ones," he said.


*SpO2 - Blood oxygen levels are indicated as SpO2, which is the percent saturation of oxygen in the blood. 

*PR - Pulse Rate (PR) The number of times your heart pulses, or beats, per minute.

PI - Perfusion index is an indication of the pulse strength at the sensor site.




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