Are Pulse Oximeters Accurate? | What Affects Accuracy?

Dependable pulse oximetry devices can be reliable, with precision ranges between +2% and -2%.

That said, accuracy, consistency, and reliability vary depending on the model you buy.

Several reports you can read online show how consumer-grade pulse oximetry devices’ accuracy varies based on manufacturer.

Hospital-grade pulse oximetry devices tend to be highly accurate and can provide the highest levels of accuracy.

These devices maintain a secure connection for continuous monitoring to detect and measure vitals, even with poor perfusion.

If you’re a consumer-grade pulse oximeter, keep the following tips in mind.

  1. Choose from a brand you know, like, and trust
  2. Look for an FDA-approved device
  3. Consult your local doctor/physician/healthcare provider on which model to buy
  4. Read online reviews and ratings to understand the pulse oximetry device’s reliability better.
  5. Read the information provided by the manufacturer/seller regarding the accuracy variance of the device

By keeping these factors in mind, you’ll stand a better chance of getting a high-quality consumer-grade pulse oximetry device.

Can Pulse Oximeters Give False Readings?

Most reliable pulse oximeters provide reasonably accurate and consistent readings.

With that said, as with any technology, pulse oximetry devices can give faulty readings.

The device’s accuracy is dependent mainly on its technology and manufacturing.

Several factors can impact reading accuracy and consistency.

These involve faulty technology, poor design, defective software, and manufacturing defects.

Even among reliable units, human and environmental factors can affect reading quality.

For instance, using the wrong, constant motion, external light sources, and intravenous dyes can impact accuracy.

Pulse oximeters are precious tools for detecting and measuring pulse rate and oxygen saturation levels.

However, they have limitations and technological issues.

Additionally, physical conditions and environmental factors can play a role in causing inaccurate readings.

To guarantee device accuracy, read the instructions, and take the necessary precautions.

It also ensures it’s operated correctly and under optimal conditions.

What Factors Can Affect Pulse Oximeter Readings?

In the previous section, I mentioned some factors affecting pulse readings.

However, this part will give you a clearer understanding of the factors that lead to false readings.

This list provides insights into elements that can alter reading accuracy and performance.

Defective/Inaccurate Technology

Using defective/inaccurate technology, pulse oximetry devices will impact reading quality and accuracy.

It can occur due to manufacturing issues or cutting corners on quality to create an inexpensive unit.

To protect yourself against an inaccurate pulse device, purchase one from a brand you know, like, and trust.

Additionally, read trusted reviews to identify potential issues or limitations to make an informed buying decision.

Poor Connection

Another factor that can affect readings has a poor connection.

A poor connection can result from using the wrong-sized probe, improper placement, or constantly moving around.

For the best results, operate your device while stationary and use a finger probe that is adequate for your finger’s size.

Additionally, proper problem placement is essential for accurately measuring light.

Using a wireless/wired probe, you’ll want to ensure a secure connection before performing a reading.

For devices that use Bluetooth, check for an adequate signal.

Also, ensure you are within range and no obstructions exist between you and the device.

When utilizing wires, ensure that it’s firmly attached to the handheld/tabletop.

Loose wires and poor signal strength can affect reading quality.

Therefore, you’ll want to keep those factors in mind when measuring your pulse rate/saturation levels.

Poor Perfusion and Existing Medical Conditions

Poor perfusion occurs when the extremities (such as the fingers and toes) receive a decrease in blood flow.

Several factors can lead to poor perfusion, including venous disorders, blood clots, obesity, and diabetes, among other health/medical conditions.

Because pulse oximetry devices rely on pulse rate/oxygen saturation levels, anything that affects blood flow can alter the reading and cause an inaccurate measurement.

Consult a doctor if you are concerned with any previously mentioned medical conditions.

They can provide information regarding these conditions’ impact on your pulse oximetry readings.

High-end devices may provide consistent accuracy, even in poor perfusion readings.

However, you should still consult a medical professional to ensure the device is accurate and effective.


Regarding accuracy, sweating is one of the known factors affecting a pulse oximeter’s reliability.

Heavy sweating can lead to inaccurate measurement, making it difficult for the probe to maintain an optimal connection.

It negatively affects the device’s light-emitting performance leading to poor pulse/oxygen saturation measurements.

Ensure your finger is clean, dry, and clear of anything affecting reading accuracy to ensure an optimal connection.

Light Issues

Lighting issues can result from external lights or obstructions on/around the finger (such as nail polish).

It can interfere with the pulse oximeter readings.

If you’re wearing heavy finger polish, consider removing it before performing a reading.

Using a device sensitive to light obstructions/variances, such as nail polish, is essential if you’re fingernails have paint.

If you’re in a setting with fluorescents/ambient lighting, consider reducing the lighting or moving to a natural environment before performing a reading.

It ensures that you’re in an optimal setting and that the lighting isn’t interfering with the pulse oximeter.

You improve your odds of getting an accurate reading by taking your measurements under optimal lighting conditions with clean fingers and a relaxed mood.

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