How Accurate Are Finger Pulse Oximeters?

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how accurate are finger pulse oximeters

Your blood oxygen saturation can tell you a lot about your health. But you don’t need a high-tech suite of medical gadgets to check your levels. Finger pulse oximeters are available to both the public and professional healthcare workers. But how accurate are finger pulse oximeters?

Keep reading to learn about their accuracy and how you can use them at home.

Commercial vs. Medical Grade Pulse Oximeters

When considering the accuracy are fingertip pulse oximeters, you should consider the different types. Commercial oximeters are available for anyone to purchase and use at home. However, medical offices and hospitals have oximeters as well.

The oximeters in a medical setting work like those you can buy. But they tend to be more accurate. These will usually be FDA approved pulse oximeters.

While you can use a commercial and home-use finger pulse oximeter to track your oxygen, most of them are for recreational use. That means you can use them to track your oxygen saturation, but they’re not supposed to treat any diseases or diagnose conditions.

Still, at-home pulse oximetry tests can be very useful. Some commercial models can be accurate like the oximeters in medical offices.

So, How Accurate Are Finger Pulse Oximeters?

The results are very encouraging! A study in the European Respiratory Journal found that commercial or home-use finger pulse oximeters correlate with actual oxygen saturation levels. This is great news for people who want to check their oxygen levels and get an idea of their health at home.

However, there are some discrepancies between the different oximeters out there. Odds are you will probably buy one oximeter and use it. In that case, you should be able to trust the variations in readings from that one device.

But if you happen to use multiple oximeters, you may not get the same reading. Two oximeters may not give the same results based on their design or some other factor, so tracking changes becomes complicated. Using the same oximeter can help you track your oxygen saturation over time.

How to Get Accurate Pulse Oximeter Readings

Commercially available finger oximeters may not always be accurate. But one reason for their inconsistency is human error. If you want to improve your pulse oximeter’s accuracy, you can set yourself up for success with a few steps.

That way, you can get an accurate reading individually or for long-term tracking. Here’s what you can do to increase the accuracy of your finger pulse oximeter.

Remove Nail Polish

If you like to wear nail polish, use your pulse oximeter before adding a new coat. Take your old nail polish off with polish remover and clean your nails.

The oximeter uses light to track oxygen in your blood, and polish could block the light signal. You could end up with an inaccurate reading even if you did everything else correctly.

If you need to use your oximeter every day but want to wear polish, you can just remove the polish from your one finger. That way, you can still get a proper reading, but you won’t have to redo your nails as often.

Insert Finger Correctly

How you place your finger in the oximeter can make a big difference in the reading you get. You should put your finger as far into the oximeter as you can then let it close. The oximeter will have more space to track oxygen in your blood that way.

So, what finger is the best for a pulse oximeter to get an accurate reading? You can use your index finger, middle finger, or thumb to test your oxygen levels. Most people use their index finger, so that’s a good finger to start with.

Make sure you use the same finger each time. When you do a test multiple times, you should keep as many factors the same to eliminate possible deviations. If you use a different finger each time, you may not get the most accurate reading.

Stay Still

When you use your finger pulse oximeter, you also need to stay still. Any motion can affect the accuracy of the device, so try not to walk around or do tasks with your hands.

While you can use an oximeter while working out, consider why you’re testing your oxygen saturation. If you’re worried about a respiratory condition or disease, you don’t need to move.

You also don’t need to have the oximeter on for a long time. Just wait long enough for the test to give a reading, and you can mark it down then move along with your day.

Medical vs. Non-Medical Use

Many commercial finger pulse oximeters are accurate. However, a lot of them are not intended for medical use. The FDA requires medical devices to have a prescription.

By that definition, most of the oximeters you can buy are not for medical use. Manufacturers may or may not state that on their packaging. You can use a finger pulse oximeter for reasons other than monitoring a respiratory condition.

Still, some oximeters do meet FDA standards. While they may not be medical devices, you can use them for medical purposes.

Oximeters without FDA approval can work well, but you need to use them correctly. You also need to remember that they’re not a substitute for proper medical care. Here’s how you can use finger pulse oximeters.

Check Your Baseline

You can use a pulse oximeter to check your baseline oxygen saturation. If you’re healthy and don’t have any major heart or breathing issues, you can get an estimate of your standard levels. Healthy levels range from 94 to 100 percent oxygen saturation.

You can use the pulse oximeter a few times over the course of a week to find patterns. That way, you can see what your average is when you’re healthy.

If you’re healthy and your oximeter is giving you a level below 94, you should call your doctor. You should visit the emergency room if your levels are below 90.

Track Your Levels Regularly

You should track your levels when you’re healthy, but if you get sick, you should also track your oxygen. Tracking your levels each day or week at the same time can help you notice patterns, and you can know when something is off.

By tracking your oxygen saturation on a schedule, you can also see how accurate your oximeter is. If you feel the same over a few days but get wildly different results, consider using a different oximeter. But also make sure you’re conducting the test the same way.

Note Serious Changes

Now, you don’t necessarily need to worry if one day your reading is 97, and the next is 96. If your oxygen saturation stays within about two percent, that means there’s not much change.

Because some pulse oximeters aren’t entirely accurate, you have to give yourself that two percent for results to differ. However, if you typically get readings at 96 or 97, you should know that.

Then, when you get a reading of 93 or even lower, you will know something is up. Serious changes may need immediate medical attention, especially if your levels dip below 90.

What About Mobile Apps?

Can You Get an Accurate Reading Using Your Phone or Smartwatch?

While finger pulse oximeters are widely available, you may not have one. If you need to track your oxygen saturation but can’t get an oximeter, you aren’t out of luck. You may be able to use your phone or smartwatch to track your oxygen.

However, these alternatives aren’t as accurate or effective as finger pulse oximeters. They only have one sensor, while finger pulse oximeters have two. The two sensors can communicate with each other to get a more accurate reading. It can also be harder to stay still when using your phone.


We have discovered that finger pulse oximeters are excellent tools to get accurate oxygen saturation readings either at home or in a medical setting.

Whether you have trouble breathing or want to check your healthy levels, you can do so with confidence, but remember to always seek medical advice if you suspect you are not getting enough oxygen.

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Written By

Stephanie Corrales

Stephanie Corrales is the Founder and Managing Editor here at HeyScrubs. As a former director of a career college for entry-level medical professionals, she offers valuable insights to aspiring healthcare professionals. In her free time she loves spending time with her husband and two children.