Pulse Oximetry Accuracy

[AragonAl]

Anyone else using the new pulse ox feature and being told that you die at night? lol! My nightly range is from 89-93%... which seems like I'm oxygen deprived at night. Of course I know that it can't be medically accurate since it's on our wrist and we move around a lot, but just wondering if anyone else is getting really low ranges. And are we all at 93% right now? I compared to 6 friends, everyone's said 93%. 

[JohnnyRow]

I disagree that it can't be medically accurate, and you are still alive.  Perhaps you are comparing to waking SpO2 levels, but sleeping SpO2 levels are lower.  According to one medical source I just looked up:
"Oxygen levels are considered abnormal when they fall below 88%."

I am not saying that it is accurate, but just that 89-93 could be reasonable.

[LeeGG]

I am also interested in the Versa 2 accuracy for SpO2.  My nightly values have varied much more than I would expect.  Two nights ago the range was 92%-95% and last night it was 97%-100%.  Over 12 nights of data, the minimum values are between 88% and 97%;  the averages are between 93% and 98%; the maximum values are between 95% and 100%.  My daytime SpO2 values with a finger pulse oximeter are consistently 96%-98%.

[anthony915]

I have been between 92 and 94 for the past 2 weeks. Now it doesn't monitor at all. totally stopped working. went on site for help and they tell me that my watch doesn't match my name. i explained to the I have upgraded my watch 2 times since being on site, but they have me check somewhere else and when I come back they are gone. What a great support group from FitBit.

[askmrhp]

My pulse and Spo2 are 2 numbers less than my pulse oximeter. 68bpm would be 70 and my Spo2 would be 95 instead of 98.

some times my pulse will match Spo2 not so much.

[t.parker]

@AragonAl it is hard to talk about accuracy when you have no access to data on demand. You can't cross-examine results with any other device and neither you can do the on-the-spot test. In such a case, I wouldn't stress too much with the results if even Fitbit isn't confident enough to release the SpO2 feature such as it could be tested for accuracy and verified against other devices.

[askmrhp]

If you have sleep apnea like I me you stop breathing for a few seconds each night . This may effect the Spo2 reading.

I can't say for sure since the watch can't give me a reading during the day. 

[SaraBice]

Pulse oximetry is a standard monitoring device in intensive care units ICUs, currently used to guide therapeutic interventions. Few studies have evaluated the accuracy of SPO in critically ill patients. Our objective was to compare pulse oximetry with arterial oxygen saturation SAO2 in such patients, and to examine the effect of several factors on this relationship. 

[JeffL01]

I have been monitoring the Fitbit (night) vs Oximeter during the day.  Big disconnect, although night time is supposed to be lower than daytime.  I think the delta is too high at 2-3%.  Anyway there is a BIG spread in daily Fitbit O2 levels whereas the oximeter is much more steady and stable.  I personally think that the Fitbit is not all that accurate as I have had medical grade oximeter readings a few time this month and they are a much better match to the oximeter than the Fitbit.

[FBWontSync2]

My FitBit gives me lower readings than my oxymeter. I think it's probable that your Fitbit along with your 6 friends are getting readings below what is accurate.  Mmy fitbit says at night my oxygen is 95-97%.  That is lower than normal for me but I am currently not near my oxymeter so I have to wait to get home to compare the accuracy.

[chrissyd98]

Same I’m between 90-94 I need to stop looking at it I am getting anxiety 😟.  

[NurseKari]

Your oxygen levels do decrease while your sleeping since your breathing is steady and slower. Your oxygen level will very based on the type of sleep you have as well; light sleep, deep sleep, or REM sleep. 90% or higher is normal oxygenation when sleeping.  Then factor in mouth breathing, illness, stuffy nose, etc. can change your O2 levels as well.  

[Jenb4c]

I just downloaded the spo2 clock for my versa 2 a couple hours ago and it’s reading  78-81 but I’m breathing fine so I’m questioning the accuracy of this 

[Brandymoreno]

His is the problem I’m having. My oxygen read as 78 last night. But I feel fine, lol. Did you ever get it figured out?

[JeffL01]

Never solved.  Delta continues to be about 2% from daytime vs.sleep.  That said, it is within the measuring error of the devices of +/- 2%.  See the latest Oximeter vs. Fitbit plot below.   this is just short of 9 months of data.

[#16]

Thanks for posting. Yeah, same here. It’s not accurate. While lower amounts may be “normal,“ it’s not healthy to have levels that low while sleeping. The heart rate is never 100% accurate either. It’s usually off by about 5 to 10% in my experience. I don’t mind that as much because in many cases one doesn’t really need an exact heart rate assessment. Oxygenation is much more acute, though, with a 5% oxygenation variation representing a much bigger difference than a 5% heart rate difference.

What’s extra frustrating is that there seem to be only responses from other users and giving their opinions and sharing their experiences, but not Fitbit employees with product knowledge explaining the latest technical details to us an answer to these questions. While the former can be helpful, the latter is what’s really needed here. Anybody with me on this? Anyway, I hope we can get some answers. Not just opinion.

[JeffL01]

I fully agree.  We can opine till we are blue in the face, but it would be great to hear from the Fitbit people.  I will update the graph every so often as well.  

[Riverb1935]

Mine was 95 % but I'm a restless sleeper 

[AllnamesRtaken]

You have the right idea... pulse oximeters are only estimates to get you "ballpark figures" and not FDA accurate (as with a blood draw, ouch!).  There are many factors that cause variations and thus inaccuracies with these devices such as skin color, smoking, room lighting, poor blood circulation due to arm and clothing positioning, etc.  It is suggested that you can expect a +/- 4% variation in accuracy with pulse oximeters vs blood draw measurements.  Since a watch does not have as secure placement against the skin, I would suppose yet another avenue for variation and thus a further decrease in accuracy is possible perhaps.  These devices are not true medical devices and are only meant to give you awareness of when you should consider seeking medical advice.  Fitbit's own advice is as follows... "The data provided by Fitbit SpO2 is intended to be a close estimation of your blood oxygen saturation levels, but may not be precisely accurate. You should not use or rely on Fitbit SpO2 for any medical purposes."  However my take on it is this: I'd rather have this estimate available to me than not... so thank you Fitbit for including it in the feature set for this watch.  So to answer your question above... so far I get an average anywhere from 93% up to 96% with my lowest in range ever being down to 90%-93%.  Remember with a recognized 4% variation for the pulse oximeter technology, my 93% average could theoretically have been as low as 89% true oxygen saturation (time to consult a medical professional) and my lowest in range could have dropped to as low as 86%, gasp!  I'm not worried however as I don't wake up continuously all night long and I feel well rested in the mornings.

[Foxycoool]

I was getting low readings, averaging 85-88 per night.  I was getting anxious and spoke to my doctor about this but he was not overly concerned since it was a wrist reading and many things can interfere with an accurate reading.  His advice (which seems to have worked) helped and my readings are 93-96 overnight.

His advice was since we tend to wear our watch nonstop with showers, exercise, cooking, cleaning, etc it is important to ensure any particles on the wrist and watch are cleaned and not interfering with the sensor:
Ensure the sensor does not have any dirt, dust, or other particle on it.  Just before bed wash your wrist and wipe the sensor area of the watch.  Lotions, dust, and other particles transferred from our skin or from normal wear can create an interference of the sensor light.  Even natural oils from our skin need to be wiped off the back of the watch or if we shower with it, water that dries on the sensor can leave a "haze" (think dried water on a window type spot).  

I started to clean my wrist where the sensor meets the skin with an astrigent cleaner or alcohol right before bed and will wipe down the back of my watch with a clean cloth (almost like polishing) and it really has helped to get a more accurate reading.  It has only been +/- 1 or 2 numbers off now instead of 10.