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.
