Fact Check: Are Oximeters showing readings for pen and biscuits?

Quick Take

A viral video on social media shows a person putting in biscuits inside an Oximeter to get readings. Another similar video shows a child put in a pen inside the Oximeter and it shows readings. The makers of these videos peddle the idea that Oximeters do not work properly and the ‘media is scaring people’ by talking about Oxygen. We fact-check and realize that while Oximeters indeed show readings even for non-living objects, there is a scientific reason for the same. We label the claim as Mostly False.

The Claim

The first viral video that we spotted showed a kid putting in a pen to get readings on an Oximeter. The video goes with a caption in Hindi, which when translated means “Why getting duped? Wake up”. The archived version of the video can be seen here and here.

The second viral video shows a person putting in 2 biscuits inside the Oximeter and a reading is displayed. Archived versions of the same can be seen here and here.

Fact Check

What is an Oximeter?

An Oximeter is a clip like medical device that uses infrared lights to detect Oxygen levels in blood. As per the website of Hopkins, ‘Pulse oximetry is a test used to measure the oxygen level (oxygen saturation) of the blood. It is an easy, painless measure of how well oxygen is being sent to parts of your body furthest from your heart, such as the arms and legs.’

How do Oximeters work?

British Lung Foundation (BLF) on its website explains, “A pulse oximeter measures how much light is absorbed by your blood. This tells us how much oxygen your blood contains. The pulse oximeter shines 2 lights through your fingertip or earlobe: one red light and one infrared light.

BPL, a leading Oximeter manufacturer further explains, ‘Small beams of light pass through the blood in the finger, measuring the amount of oxygen. It does this by measuring changes in light absorption in oxygenated or deoxygenated blood. The pulse oximeter will thus be able to tell you your oxygen saturation levels.’

Source: BPL Website
Why do Oximeters show readings for pens, biscuits, and other non-living things?

BPL recognizes this on their website and provides a scientific explanation to it. ‘The patient’s condition is detected based on the sensitivity of the amount of red and infrared light falling on the sensor of the pulse oximeter or probe in other machines. When this is obstructed by increasing the distance between the LED and the detector, or by inserting some object inside the probe, the module will think the finger is inserted and will start searching for a pulse. In this condition, the varying intensity of diffused light falling on the detector can cause a pulsating effect and lead to a reading on the pulse oximeter. The pulse oximeter is a very sensitive device. However, if the gap between the LED and the sensor is closed fully, so that no light falls on the detector, the pulse oximeter will sense no pulse and there won’t be any reading.

This explains why readings were shown on the video when non-living objects were inserted in the oximeter. However, this does not mean that the readings that a oximeter gives on a human finger is fake.

BPL strictly advises against  insertion of any objects like a pencil, pen, etc in the pulse oximeter to check the readings as it may damage the sensor of the device and can lead to malfunctioning. 

Are Oximeters necessary?

Oximeters are a necessary device for doctors, primary healthcare workers, sportsperson, high altitude trekkers etc. It gives an indication on whether the person’s lungs are performing well and he is being able to get enough oxygen in his body.

Lower levels of Oxygen in the body for long can have serious health implications including headache, dizziness, chest pain etc. Understanding the underlying health reason for these symptoms are very important for medical professionals to decide on the course of treatment.

Having Oximeters at home is a debatable recommendation from doctors. If there are patients at home who have pre-existing lung diseases, having an eximeter may help. During the COVID-19 pandemic, since the Coronavirus is known to attack lungs, many people opted for having an Oximeter to measure their Oxygen saturation at home.

The Ministry of Health and Family Welfare (MoHFW) in a document titled “Home care tips for managing COVID-19” recommended people having COVID-19 and undergoing home treatment to monitor their oxygen levels with a pulse oximeter 3-4 times in a day.

Are Oximeters dependable?

As per the website of FDA, ‘pulse oximeters are least accurate when oxygen saturations are less than 80 percent and most accurate when the oxygen levels are between 90-100 percent.’ Therefore, the FDA advises to monitor trends over time instead of absolute thresholds.

How to use an Oximeter?

IndiaCOVIDSOS, a volunteer group consisting of scientists, clinicians, engineers, policy-makers and epidemiologists, has recently published a video explaining how to use a pulse oximeter at home.

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