I have an Apple watch and use the BloodOx feature on that. Apple just recently lost their license to sell that technology so the newest versions don't have the feature. I use my watch also for Afib alerts and taking my own ECGs.

Hi Glenda, l would check the battery. Also, wash your hands in warm water first. If your hands are cold from being outdoors, that may affect your reading. Be sure it is applied properly. If.the nail side. Of the.oximeter is over the fleshy part of the finger, it may not register a correct reading! Best wishes and Blessings to you!!!

Do you have gel or dip powder on your nails ? That could be why.

It is very weird but my left hand is always 10 pts lower than my right.

I think it will for me. I could see the readings through the night. I hate every doctor visit when they use the finger oximeter and I tell them it won't read right or not at all. Thanks for letting me know others have the same issue