For The Most Accurate Read, Where Should You Put That Thermometer? 
 
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 To get the most accurate measurement of the body's temperature, a rectal thermometer works best, a study finds. Less invasive methods to measure body heat on the outside of the skin such as on the forehead or under the arms just aren't as precise. 
 
 Now does this mean everyone should rush out and restock their medicine cabinet with rectal thermometers? Probably not, says Dr. Daniel Niven, an intensive care physician with the Peter Lougheed Center in Calgary, who headed a review of the effectiveness of different types of thermometers. He says the oral thermometer and ear thermometer are reasonably accurate options. 
 
 Niven and colleagues analyzed data gathered from 75 studies from around the world, involving more than 8,600 patients, both adults and children. They wanted to know how the various types of thermometers compared. They looked at measurements taken in the armpit, mouth, ear and on the forehead, called peripheral thermometers. 
 
 They compared those measurements to each other and also to measurements from more invasive thermometers called central thermometers, like one placed inside the rectum or inside the bladder, used for hospitalized patients with catheters. The results were published Monday in Annals of Internal Medicine. 
 
 They found peripheral thermometers could be off as much as 1.5 degrees. 
 
 The more invasive measures were the gold standard, Niven says, enabling doctors to make diagnoses in patients without obvious symptoms. This is important because if a temperature measures as normal when it's not, then a serious infection could go undetected. This is especially critical in hospital intensive care units, he says, where "important opportunities to treat significant infections" may be overlooked. 
 
 Many ICUs rely on armpit measurements, he notes, not rectal or bladder measures. Niven hopes the findings of this study will encourage hospitals to rely more on central thermometers. 
 
 As for parents of children with more minor infectious illnesses such as a cough, runny nose or sore throat, thermometers measuring temperature in the mouth or ear provide a more accurate temperature reading than armpit or temple thermometers, the researchers found. Niven says that in these circumstances, people can generally rely on using these thermometers and need not resort to less comfortable thermometers, such as the often dreaded rectal thermometer. 
 
 Niven's study didn't include infants or toddlers, so he says he can't make recommendations for parents in taking temperature for this age group. But the American Academy of Pediatrics does recommend rectal thermometers as the most accurate for children under age 3. 
 
 Normal temperature is often thought of as 98.6 degrees, but there's a surprisingly wide range for normal. Between 97 and 99 is considered to be in the normal range of body temperature. ||||| Rectal Thermometer Remains Gold Standard for This 
 
 Better than temperatures taken by mouth or under arm, study says 
 
 
 
 WebMD News from HealthDay 
 
 By Robert Preidt 
 
 HealthDay Reporter 
 
 MONDAY, Nov. 16, 2015 (HealthDay News) -- Although it's no one's favorite method, a rectal thermometer is the best way to determine someone's body temperature, experts say. 
 
 Accurate body temperature readings are important because they are used to make diagnoses, check for infectious diseases, evaluate whether or not a treatment is working, and guide patient management, the study authors explained. 
 
 Rectal thermometers are considered the gold standard, the researchers said. But the accuracy of thermometers used in the mouth or under the arm (peripheral thermometers) has been unclear. 
 
 So, the researchers reviewed 75 published studies. They found that peripheral thermometers are less accurate than rectal thermometers, particularly for low-grade fevers. 
 
 The findings were published online Nov. 16 in the journal Annals of Internal Medicine. 
 
 Health care workers should use rectal thermometers when a patient's temperature will influence diagnosis and treatment, the researchers said in a news release from the American College of Physicians. 
 
 Rectal thermometers can be used for most children and adults. When that isn't possible, a calibrated ear thermometer (or a bladder thermometer for patients with bladder catheters) are good alternatives, according to Dr. Daniel Niven from Alberta Health Services in Canada, and colleagues. ||||| An exhaustive, 24-page article released Tuesday in the Annals of Internal Medicine shows that taking body temperature rectally is most accurate, short of actually sticking a needle in a vein. 
 
 That finding confirms that these types of thermometers are more accurate than so-called peripheral thermometers: those that are held under the tongue, laid across the forehead or against the temple, tucked into armpits, and gently placed in ear canals. But how important is it to get super-precise temperatures? 
 
 In the latest study, researchers reviewed 75 published studies comparing peripheral thermometers with central ones — mostly either temperatures taken from a vein or from the rectum. 
 
 They found that rectal thermometers were highly accurate. Peripheral thermometers were further off, with oral thermometers doing best among the runners-up. 
 
 The peripheral thermometers were especially inaccurate in patients with very high fevers. At those extremes, thermometers in armpits and ears could read “as much as one to two degrees higher or lower than actual body temperature,” the researchers wrote. 
 
 But does a degree or two one way or the other really matter? More importantly, does it matter enough to warrant sticking a thermometer where the sun don’t shine? 
 
 Lead researcher Dr. Daniel Niven of the University of Calgary said the one- to two-degree difference is not a problem for most people. 
 
 “If you have a fever from a cold or something like that, then you can use an oral thermometer, which is a bit more accurate than the (armpit or ear thermometers). 
 
 “But there are select circumstances where accuracy really matters,” he added. 
 
 The researchers determined that peripheral thermometers are especially bad at detecting low-grade fevers. Catching these more subtle rises in body temperature is important in early detection of infection or illness in particularly vulnerable patients — the elderly, the immunocompromised, or patients with tumors or with connective tissue disease. 
 
 The temperatures of such patients tend to be closely monitored already. But Niven said that the most accurate thermometers are not necessarily the most used. 
 
 “There’s not data to show what thermometers are being used where, but anecdotally, the primary method used in ICUs are axillary (armpit thermometers),” said Niven, an intensive care physician. 
 
 But for regular consumers, Niven has just this one piece of advice: Don’t use armpit thermometers. “They are the least accurate,” he said. 
 
 Leah Samuel can be reached at leah.samuel@statnews.com 
 
 Follow Leah on Twitter @leah_samuel 
 
 
 

– In what STAT describes as an "exhaustive" 24-page report, there's one type of thermometer that rises above the rest when it comes to gauging body temperature. Rectal thermometers remain the "gold standard" for getting the most accurate reading, HealthDay News reports, even though "it's no one's favorite method." For the study appearing in the journal Annals of Internal Medicine, researchers examined 75 published studies, comprised of more than 8,600 patients total, that compared "central" thermometers (i.e., either rectal ones or those that can get temps from a vein) with "peripheral" ones—the kind we stick under our tongues, in our armpits and ears, and on our foreheads, STAT notes. The results: Rectal thermometers were "highly accurate," while peripherals didn't perform as well, especially in detection of low-grade fevers and accuracy in measuring high-grade ones (the study found ear and armpit thermometers could be up to two degrees off in either direction). For most people with a minor cold, that isn't a big deal, lead author Dr. Daniel Niven tells STAT. But when you're dealing with certain groups—including older patients, those with immunity issues, and patients with tumors—it's critical to use the most accurate thermometers that can pick up even the slightest fever, the study notes. The least-accurate instruments for temp-taking? Armpit thermometers, Niven says. The study didn't include infants or toddlers, so the recommendation to use rectal thermometers can't be extrapolated to them based on this study, NPR notes, though it adds that the American Academy of Pediatrics gives a thumbs-up to rectal thermometers as the most accurate for kids under the age of 3. (Toucans don't need thermometers—they've got their own beaks to keep things in balance.)