Thermometers & oximeters
Let’s run through the details of two medical devices that can help you monitor your health at home
As a high temperature is a symptom of COVID-19 (coronavirus), it’s useful and recommended to have a thermometer at home in your first aid kit. A pulse oximeter can be useful for those who have tested positive for COVID-19, whose symptoms are generally mild and being treated at home. The oximeter is a helpful device for checking oxygen saturation levels so low oxygen levels can be caught early.
What's a thermometer?
A thermometer is a device that measures your body temperature. There are several different types of thermometers available, including digital thermometers, electronic ear thermometers and infrared thermometers. It’s always helpful to have a thermometer at home – especially if you have children. When using any kind of thermometer, make sure you read and follow the instructions that come with it. If your thermometer uses batteries, check them as weak batteries can give inconsistent readings.
What's a high temperature?
Normal body temperature is different for everyone and changes during the day. A temperature of 38°C or more is usually considered to be a high temperature.
There are many different things that can cause a high temperature, but usually it’s because your body is fighting an infection. You may have a high temperature if:
• A thermometer says your temperature is 38°C or above
• Your chest or back feel hotter than usual
• You have other symptoms, such as shivering (chills), sweating or warm, red skin
A high temperature could be a sign of COVID-19. If you have symptoms of COVID-19, including a high temperature, you should follow government guidelines and get a free NHS COVID-19 swab test to check if you have the virus.
How do I use a digital thermometer?
A digital thermometer is a fast and accurate way to measure your temperature. Readings can be taken from under the tongue or under the armpit. To use a digital thermometer:
1. Clean the tip with cold water and soap, then rinse it
2. Turn the thermometer on
3. Put the tip under the tongue
4. Close lips around the thermometer
5. Wait until it beeps or flashes
6. Check the temperature on the display
If you use your digital thermometer in your armpit, make sure you keep your arm tight against your body until the thermometer beeps or flashes.
What's an oximeter?
A pulse oximeter is a non-invasive, electronic device that uses a sensor placed on your fingertip or earlobe. It measures your blood oxygen levels. Oxygen enters your lungs when you breathe in. It enters into the bloodstream where it’s then picked up by red blood cells and carried around the body. The pulse oximeter device uses infrared light to measure how well oxygen binds to the red blood cells. The reading it gives is called peripheral capillary oxygen saturation (SpO2). A person's blood oxygen level helps to show how well oxygen is carried from the lungs all over the body. If blood oxygen levels dip too low, you can become unwell. In a healthy person, a healthy SpO2 reading is 95 percent or above.
Research has found that some people with the COVID-19 virus develop ‘silent hypoxia’ – a condition where oxygen levels in the body are very low without showing obvious symptoms. A pulse oximeter can help you measure and monitor your blood oxygen levels at home. Blood oxygen levels may be lower in some people with chronic lung conditions even when they are well.
How do I use an oximeter?
Make sure to take your pulse oximeter reading whilst sitting quietly and comfortably. Place your clean finger into the device and try to stay as still as possible. Keep your hands as steady as you can and avoid shaking the device. Wearing false nails or nail varnish may affect the accuracy of your reading.
Can a thermometer or an oximeter diagnose COVID-19?
While both devices can help you monitor your health at home, neither can confirm a COVID-19 diagnosis. The only way to know for sure if you have a current COVID-19 infection is to have a swab test.
If you have symptoms that you're concerned about or are worsening and you don’t have a COVID-19 infection, you should speak to your GP about your symptoms.
Information correct at time of publication (12.01am 19/01/2021)