Reply
 
Thread Tools Display Modes
  #1  
Old 05-19-2020, 06:15 AM
Dahu is offline
Guest
 
Join Date: Mar 2008
Location: Manchester, England
Posts: 541

Advice on buying infra-red thermometer for body temperature


Not sure if this is the right forum, but here goes.

I work for a gym. We're currently closed but putting in measures ready for reopening. We're considering temperature checking every user coming in using a contactless IR thermometer. This would be an initial check, an unusual reading would have the user pulled to one side and asked further questions.

Are these things accurate enough? Worried about too many false-positives here.

And if the are good enough, can anyone recommend a decent model?
  #2  
Old 05-19-2020, 09:18 AM
engineer_comp_geek's Avatar
engineer_comp_geek is offline
Robot Mod in Beta Testing
Moderator
 
Join Date: Mar 2001
Location: Pennsylvania
Posts: 26,639
I have one that work gave me. We also have one at work by the front entrance. While most of us are working from home, if we need to go into the office for any reason we are required to check our temperature and record it. If it is too high, you have to go home. No exceptions.

The one we have seems to read a little low, but it works well enough.

I just picked up the box to get the brand name off of it, and there is no brand name whatsoever on the box. The only identifier on the box is "Item No. BLIR-3".

I can't compare it to any others since this is the only one that I have ever used.

Work also gave me an Osport pulse oximeter. Seems to work pretty well, but they printed the instructions in micro-text that I could not even begin to read even with my glasses on.
  #3  
Old 05-19-2020, 09:32 AM
Crafter_Man's Avatar
Crafter_Man is offline
Member
 
Join Date: Apr 1999
Location: Ohio
Posts: 11,712
I'm not sure how accurate they are. But if you're going to buy one, I recommend a unit that is designed to measure forehead temperature. Something like this.
  #4  
Old 05-19-2020, 09:42 AM
Pixel_Dent is online now
Guest
 
Join Date: May 2011
Location: Raleigh, NC
Posts: 1,168
We use one of these and it works well for us... https://www.thermoworks.com/wand

Forehead temperature is roughly 1 degree F lower than oral temperature. The thermometer I linked makes that conversion. Someone else said they thought theirs read a bit low. It could be that theirs is perfectly accurate but not making the "forehead to oral" conversion.
  #5  
Old 05-19-2020, 12:11 PM
DPRK is offline
Guest
 
Join Date: May 2016
Posts: 5,123
Quote:
Originally Posted by Dahu View Post
Not sure if this is the right forum, but here goes.

I work for a gym. We're currently closed but putting in measures ready for reopening. We're considering temperature checking every user coming in using a contactless IR thermometer. This would be an initial check, an unusual reading would have the user pulled to one side and asked further questions.

Are these things accurate enough? Worried about too many false-positives here.
Disclaimers and all that, but if your intention is to screen out people with an elevated body temperature, I would worry that, no, it is not at all accurate.

First problem is the calibration and correction for emissivity value of different types of skin. Secondly, skin temperature can vary between 33.5 and 36.9 depending on where you measure it, and also depends on the air temperature, patient's gender, and all sorts of other factors (eg see here). Are you prepared to deal with all that? Last time I was in a hospital, they measured under the tongue.
  #6  
Old 05-19-2020, 12:28 PM
Chronos's Avatar
Chronos is offline
Charter Member
Moderator
 
Join Date: Jan 2000
Location: The Land of Cleves
Posts: 88,641
Infrared thermometers can be made far more accurately and precisely than would be needed for any medical purpose. They can also be made cheaply with far inferior precision and quality. You'll have to do research on the brands and models that you're looking at.
  #7  
Old 05-19-2020, 12:34 PM
TroutMan's Avatar
TroutMan is offline
Member
 
Join Date: Sep 2008
Location: Portland, OR
Posts: 5,376
Quote:
Originally Posted by DPRK View Post
Disclaimers and all that, but if your intention is to screen out people with an elevated body temperature, I would worry that, no, it is not at all accurate.

First problem is the calibration and correction for emissivity value of different types of skin. Secondly, skin temperature can vary between 33.5 and 36.9 depending on where you measure it, and also depends on the air temperature, patient's gender, and all sorts of other factors (eg see here). Are you prepared to deal with all that? Last time I was in a hospital, they measured under the tongue.
It's certainly not accurate for a definitive reading, and you are correct that values can vary by people, time of day, etc. But they can still be a good solution for initial screening. I visited a hospital last week, and was scanned on my neck with a touchless IR thermometer on entrance to the building and again at the entrance to the lab. The medical staff doing the scanning trust this method well enough to use it.
  #8  
Old 05-19-2020, 02:46 PM
Crafter_Man's Avatar
Crafter_Man is offline
Member
 
Join Date: Apr 1999
Location: Ohio
Posts: 11,712
Did a little research, and there are some who believe more consistent and accurate results could be obtained if the IR thermometer measured the temperature of the inside of the mouth. The person-under-test would open their mouth, and the tester would point the LED at the back of the throat.
  #9  
Old 05-19-2020, 04:04 PM
TroutMan's Avatar
TroutMan is offline
Member
 
Join Date: Sep 2008
Location: Portland, OR
Posts: 5,376
Quote:
Originally Posted by Crafter_Man View Post
Did a little research, and there are some who believe more consistent and accurate results could be obtained if the IR thermometer measured the temperature of the inside of the mouth. The person-under-test would open their mouth, and the tester would point the LED at the back of the throat.
That might be true, but having people open their mouths and breathe in your face is not a good idea with a disease that can be transmitted by aerosols.

And if you're using an IR thermometer designed for foreheads, it has a temperature correction built in so it shows the presumed internal temp based on the forehead temp. You'll get a less accurate reading if you use that on a spot inside the mouth.
  #10  
Old 05-19-2020, 04:18 PM
filmore is offline
Guest
 
Join Date: Aug 2002
Posts: 5,021
Since it measures skin temperature, it's probably designed assuming the person being tested is indoors and calm. It may be thrown off if someone's skin is abnormally hot from something external like standing in the sun or working out. I would think this might be a concern at a gym where people might have been standing outside waiting to get in or ran to the gym as part of their exercise routine. You should do some test runs with your trainers in the gym to see if that's true. Take the trainer's temp and then have them work out hard and see how their temp changes.
  #11  
Old 05-19-2020, 04:32 PM
running coach's Avatar
running coach is offline
Arms of Steel, Leg of Jello
Charter Member
 
Join Date: Nov 2000
Location: Riding my handcycle
Posts: 38,267
Quote:
Originally Posted by TroutMan View Post
That might be true, but having people open their mouths and breathe in your face is not a good idea with a disease that can be transmitted by aerosols.

And if you're using an IR thermometer designed for foreheads, it has a temperature correction built in so it shows the presumed internal temp based on the forehead temp. You'll get a less accurate reading if you use that on a spot inside the mouth.
I just used a kitchen IR thermometer on both spots. I got consistent readings of only .2-.3 difference.
  #12  
Old 05-19-2020, 04:54 PM
TroutMan's Avatar
TroutMan is offline
Member
 
Join Date: Sep 2008
Location: Portland, OR
Posts: 5,376
Quote:
Originally Posted by running coach View Post
I just used a kitchen IR thermometer on both spots. I got consistent readings of only .2-.3 difference.
And the forehead reading was 0.2-0.3 degrees more accurate.

In general, a forehead temperature is 0.5-1.0 F (0.3-0.6 C) lower than an under-tongue temp. The tongue surface or back-of-mouth temp is probably between those two, so your measurements make sense.
  #13  
Old 05-19-2020, 05:25 PM
Sunspace is offline
Charter Member
 
Join Date: Jun 1999
Location: Near the GT eeehhhh...
Posts: 27,956
I just bought a Braun BNT400CA no-touch thermometer. We have to take our temperatures each day before going to work (when we are recalled). You aim it between the eyebrows. There is a light to help aim. The manual said that it reads about half a degree (Celsius) low.
__________________
Rigardu, kaj vi ekvidos.
Look, and you will begin to see.
  #14  
Old 05-26-2020, 08:40 PM
Alpha Twit's Avatar
Alpha Twit is offline
Guest
 
Join Date: Jun 2009
Location: Somewhere south of normal
Posts: 2,711
My employer just started testing us with THIS bit of awesomeness. The TI480 from Fluke. The powers that be seem to think it's an impressive bit of kit.
__________________
There's plenty few problems in this life that can't be helped by a good day's work, a good night's sleep and a few swift kicks in the right asses.
  #15  
Old 05-26-2020, 08:48 PM
running coach's Avatar
running coach is offline
Arms of Steel, Leg of Jello
Charter Member
 
Join Date: Nov 2000
Location: Riding my handcycle
Posts: 38,267
Quote:
Originally Posted by Alpha Twit View Post
My employer just started testing us with THIS bit of awesomeness. The TI480 from Fluke. The powers that be seem to think it's an impressive bit of kit.
Under 10 grand. What a bargain!
  #16  
Old 05-26-2020, 08:51 PM
Sunspace is offline
Charter Member
 
Join Date: Jun 1999
Location: Near the GT eeehhhh...
Posts: 27,956
Quote:
Originally Posted by Alpha Twit View Post
My employer just started testing us with THIS bit of awesomeness. The TI480 from Fluke. The powers that be seem to think it's an impressive bit of kit.
We played around with a thermal imager when I was in architecture school. People heat up in the most interesting places when they get embarrassed...
__________________
Rigardu, kaj vi ekvidos.
Look, and you will begin to see.
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 12:50 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2020, vBulletin Solutions, Inc.

Send questions for Cecil Adams to: cecil@straightdope.com

Send comments about this website to: webmaster@straightdope.com

Terms of Use / Privacy Policy

Advertise on the Straight Dope!
(Your direct line to thousands of the smartest, hippest people on the planet, plus a few total dipsticks.)

Copyright 2019 STM Reader, LLC.

 
Copyright © 2017