How do ear thermometers work?

[FirstTimer2020]

I've bought myself the Braun 7 ear thermometer because I wanted more accurate readings for my baby. I checked her ear (that she wasn't lying on) before she woke up and it was 34.7 - I checked her other ear (the one she was lying on) which was 36.6 and her stomach was nice and toasty so that's the reading I went by.

I thought these things were supposed to be super accurate but to me, it just confirms that it isn't just checking core temperature and air temperature also plays a role.

Am I right? Can someone please explain?

How old is your baby? Because I've heard that the younger the baby is the less accurate as their little ear canals are not big enough to properly fit the nib of the thermometer into. I think that's why they advise underarm or mouth thermometers for under 1 year olds.

They have a tendency to under read in my experience and much worse with a smaller baby. It’s possible to get an accurate reading but involves practicing the positioning. Lots of people (and our nursery) use forehead IR sensor thermometers now but I don’t think they’re super accurate either. I don’t think you’re particularly looking for the second decimal place either really, but once positioning is ok, then you can tell the difference between 36/37/38/39+

I have the same issue - when I try to use thermometers on myself I never know how far in to push it! If I push it in, then it always says I've got a fever, but if I hover around the entrance to the ear canal then it reads ok. I usually just use an underarm one on my son and a mouth one on me as I don't think the ear ones are that accurate...

They shouldn't be used in under ones.
They are not accurate because of user error, it's all about getting the sensor in the correct position.
They work by reading the temperature of the tympanic membrane which shares the same blood supply as the hypothalamus which is the body's thermostat.
They tend to read a little bit higher than under arm and rectal thermometers.
We stopped using them on our ward years ago because of user error.

She's 3 months old - the thermometer has a specific setting for 0-3 months, I didn't realise they weren't recommended! The only reason I bought it was because my DD sleeps like a starfish in her sleeping bag so her armpits are usually not an accurate place to measure her temperature either! 😂

personally I think they're crap for anyone, we use them in the nhs on wales and if you took a reading then did it again immediately after it would give you a different reading. So they're not at all accurate. Old school auxiliary thermometers are the best even though they're a pain to use on little ones