What are the different types of at-home thermometers?
Your basic digital thermometer options to choose from are:
- Single-use stick thermometer (marketed for rectal only)
- Multiuse stick thermometer (rectum, mouth, or armpit)
- Tympanic thermometer (ear)
- Temporal artery thermometer (forehead)
- Tympanic and temporal thermometer (ear and forehead)
- Infrared non-contact thermometer (forehead)
All thermometers sold in the United States must meet federal standards and are already calibrated for home use at the time of purchase.
Which type of thermometer is the most accurate?
Only a rectal temperature offers a true outpatient reading, says pediatrician, Dr. John Vann. "Everything else is an estimate," he said.
"Luckily, the exact number is not usually as important as how the patient looks," he adds. This is to say, there are other indicators of how severe someone's illness or condition is other than an optimally accurate temperature reading. There are also reliable methods for checking your temperature even if you don't have access to a thermometer.
No matter if you opt for an infrared thermometer or a strictly ear-based model, it's important to know fever isn't the same for everyone and that it varies by age, gender, and time of day, among other variables. Using a thermometer at various times of the day when you're feeling well gives you an idea of what's normal for you, or your baseline temperature.
Which is the best thermometer for home use?
Among at-home thermometers, medical research hasn't determined an exact correlation between oral, rectal, ear, armpit, and forehead temperature measurements. But Kaiser Permanente notes that an ear (tympanic) temperature is 0.5 to 1 degree higher than an oral temperature and a forehead (temporal) scanner is usually 0.5 to 1 degree lower than an oral temperature.
Can I use my HSA/FSA funds to buy a thermometer?
If you have an HSA or an FSA account, know that over-the-counter digital thermometers are eligible for reimbursement without a prescription.
Here's how it works:
- If you pay with cash or credit card in a store or online, you can request a reimbursement from your HSA/FSA account. Different plans have different requirements on what's needed for reimbursement but usually, a copy of your thermometer receipt will be enough.
- There are HSA and FSA-specific retailers, like the HSA Store and the FSA Store that make shopping for items that qualify for reimbursement simple. According to both websites, when shoppers use an HSA or FSA card to pay, they typically don't have to submit receipts. Purchases on these websites automatically substantiate. It is worth noting, however, that the thermometer options available on these websites are limited and cost more than other retailers.
What counts as a fever?
To figure out what's a fever for you, you want to find your baseline temperature (i.e., what's normal for you) by checking your temperature at various times of the day when you are feeling well.
While many Americans think anything over 98.6 degrees Fahrenheit is a problem, what constitutes a fever is different from person to person.
Rik Heller, a biomedical engineer, and thermographic expert, told Insider, "Age, gender, and even time of day impact normal body temperatures."
Some children's temperatures especially run higher than others, points out Dr. Jesse Hackell, a practicing pediatrician with New York-based Pomona Pediatrics. Any reading of 100.4 F or higher in a baby younger than 3 months is a reason to call the pediatrician. "Another reason to call is if the fever persists for more than 24 hours in children younger than two and more than three days in a child 2 years of age or older," he said.
Meanwhile, older adults tend to have lower baseline temperatures than younger adults, and fevers in the elderly are sometimes completely absent.