Q: “Are digital thermometers as reliable as the older glass standard ones?

January 29th, 2013 by cathay

Q: “Is there any difference between a regular thermometer and an electronic [digital] one? Someone told me the electronic ones are not very reliable when trying to tell if someone has a fever. Is that true?”

Thank you for your question about the reliability of digital thermometers when compared to the glass, mercury-filled ones many of us grew up with. It’s important to know if our tools are giving us the right readings!

One of the best sources for finding information about the reliability of certain products is “Consumer Reports”. Our Delaware Libraries offer free access to this popular magazine online and in our libraries. Online, you just need your library card number (located on the back of your library card) and your PIN to log into the “Magazines” area. Once there, you can search by publication or subject to find articles.

For your question, I searched on ‘Consumer Reports’ for studies about the reliability and accuracy of digital thermometers and see that the most recent article is titled, “Hottest fever thermometers” (Nov2011, Vol. 76 Issue 11, p7-7). In this article, the authors identify some discrepancies with digital thermometers but emphasize that it is small. They state:

“The most accurate thermometers were within 0.5 degree of our medical thermometer, and all but one were at least good at repeating a retaken temperature. The exception: the lowest rated Vicks ComfortFlex.”

Further details, including the ranking of a variety of products, are provided on the article available through the Delaware Libraries, and other information about thermometers is freely available on Consumer Reports’ site.

The National Institutes of Health and the US EPA (Environmental Protection Agency) also give excellent information about today’s thermometers. They describe the move from the standard glass, mercury-filled thermometers, how to dispose of these, and what to consider when purchasing an electronic thermometer. If you are looking for a way to get rid of that old standard thermometer, the EPA suggests giving it to your primary doctor since mercury is toxic.

Batteries are another consideration since they can affect readings when low, and like all batteries, need to be disposed of properly. Not all digital thermometers have replaceable batteries, though. It’s just one more feature you may like.

One final bit of information that might come in handy is an article on how to take a person’s temperature (orally), on Drug Information Online’s site. This handy article offers suggestions too, such as writing down a person’s temperature and the time taken to keep a record.

I hope this completely answers your question; please feel free to ask your Delaware Libraries anytime, in person or online using our live, chat library service called Ask a Librarian Delaware. We hope to see you in our libraries and online using our resources soon!

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9 Responses to “Q: “Are digital thermometers as reliable as the older glass standard ones?”

  1. Olumide Oluwasegun says:

    I think a lot of problems with our digital thermometers stem from bad batteries! We most times do not remove the batteries on time and they start fluctuating when giving readings. As stated above, we should note this on time and make sure we dispose of them properly

  2. martijn says:

    I believe that the digital ones never give the right temperature….

  3. Mellion says:

    For me, the best one is the classic traditional one. Modern technology makes everything a bit too complicated and messy at times.

  4. cosmic says:

    Batteries would certainly be a consideration, and also the way the thermometer has been treated (eg thrown in the desk draw) – With glass and mercury, damage to the thermometer is obvious. Interesting question, thanks!

  5. Rrobyf says:

    I believe that the digital ones never give the right temperature!!

  6. Lee says:

    I would concur on the classic thermometer i definitely grow up with it. And the best part is you don’t have to be worrying on batteries.

  7. storm says:

    I’ve been sick with a fever for a couple of days. I woke up this morning with very bad chills. I took my temp with a digital thermometer and it read 97.7. I knew that couldn’t be right and dug up an old glass thermometer. It said my temp was 100. Not throwing away the glass and mercury one out but the digital one is gone. If it helps the digital one is ReliOn.

  8. Limax says:

    I do not have much faith in readings of digital thermometers since I have made an experiment. I took several digital thermometers used in our lab and several old mercury-filled glass thermometers and put them into controlled environment for an hour to reach equilibrium. While mercury thermometers showed exactly the same readings, there was almost 1 degree celsius range in digital thermometers. Sorry for my english.

  9. G says:

    I am 68 years old and all of my life my normal temperature has been 98.6 read on mercury thermometers. I have never been able to find any digital thermometer that would read my normal temperature at 98.6 or for that matter the same temperature twice and in addition there is nothing as sterile as a glass thermometer. I wish they still sold them.