I'd think that it would be whatever your temperature is when it's taken. I would doubt that one part opf your body's make-up would be different temperature wise than another part. Though one thing, and that is-if you take an oral reading soon after ingesting something cold, then yes, perhaps what the thermometer registered, in fact might be giving a different reading than what it is in your veins and arteries. If you get a more definite answer or are advised by a medical person, please post and let us know.