Can two different thermometers be wrong?

[Goblin74]

Morning everyone,

My son has had a virus the last week (3 days he had a temperature, then the viral rash came 48 hours after last temp). I was checking his temp yesterday (armpit) and getting ridiculously low readings like 35.1 - 35.6. I knew they couldn't be right as he wasnt cold to touch, was playing and happy but I was worried regardless. Then I decided to take DH and my temperatures too and I got similar results : 35.4 and 35.5. I relaxed after this thinking the thermometer was just incorrect.

However this morning, I've found the other one and they are displaying the same temperature as each other. Under arm this morning was 35.6 for me and 35.9 for my son.

Could both be wrong? Or are DH, DS and myself just cold people 😆?
In a serious note, I'm wanting to make sure my son is doing ok as it's the first time he's ill (10 months old) and I'm a bit nervous! (We've spoken to doctors too, they say it's just a virus)

Thanks all.

I run low as does my son always has. My heart rate is also low as is my blood pressure same for
My boy ( he's been in and out of hospital for a few health conditions and it is written in his notes)
I use a zappy thermometer (like a gin) under arm is harder to keep still for a little one.

*gun not gin!!!!

When you take an armpit temperature it's meant to be lower than an oral or forehead reading. You're meant to add on 0.5 - 1 degree. It should say in the instructions for the thermometer somewhere, or you could Google it.

Thanks @Fooshufflewickjbannanapants I was going to try a different kind of thermometer to get a better reading as my son dislikes it already and starts to whinge when I bring it out so he's quite wriggly.

@Motherissues2020 see I did think you had to add 0.5 - 1 degree but when I was googling last night everything was saying a normal temperature for under the arm was 36.5 so I was a bit worried to see 35.1 - 35.5. I will read the instructions though and see if it has it in there!

Yes but if you add 0.5 - 1 degree then you're within the normal range. You could all run just a little cold, or your temps can change over the course of a day and it depends what you've been doing etc.

I'd suggest getting an ear thermometer like they have in the doctors. I got the original Braun one which is now 19yrs old and it still works a great.

@Motherissues2020

Yes but if you add 0.5 - 1 degree then you're within the normal range. You could all run just a little cold, or your temps can change over the course of a day and it depends what you've been doing etc.

Yes, this. My ds stayed in hospital a lot as a child and they’d always check if you’d added the 0.5-1 degree when you gave them his temperature at home over the few days before he came in. They also added the half - one degree themselves when taking it.

Thermometers give different readings from different parts of the body, and also people's 'normal' body temperature is from a range, not one classic figure for all.

So you need to find out at times when you are well what your normal is on that particular thermometer (yes they do vary)

I know that I tend to run on the low side, and that if I was reading over 37 then I am running a temperature for me. But I also know I wouldn't have a hope of convincing anyone else that that reading was unusual - glad to see that MagpieSong's experience is different

When I was in hospital, hot day in August , before having my daughter I was hypothermic, tried two thermometers, same result. I'm always at the low end of normal anyway.