Confronted by the ever-expanding world of thermometers, parents are often confused by which kind to buy and what temperature-taking technique to use.
Many physicians recommend taking rectal temperatures -- especially for newborns -- because the thermometer measures closest to the core body temperature. However, parents must be careful to properly insert the thermometer so as not to perforate the bowel and should consider using an unbreakable plastic thermometer.
Axillary, or underarm, temperatures are less invasive and less accurate; so are forehead fever strips. Children under the age of 5 usually have difficulty with oral thermometers.
Some physicians caution against the tympanic, or ear, thermometer -- which can give a reading in 1 second -- because of the difficulty of getting a consistent reading unless the temperature-taker is properly trained.
"Theoretically the thermometers are terrific because they're not invasive," says Baltimore pediatrician Timothy F. Doran. "But you have to know how to point the mechanism right at the eardrum. I got different readings than the nurses did from the same patient."
Dr. Jean Ogborn, instructor of pediatric emergency medicine at Johns Hopkins Hospital, says she got seven different temperatures from her own ear within 5 minutes.
"We've also found there are a lot of children -- especially under theage of 3 -- who hate having anything put in their ears."
Conventional thermometers will register about 90 percent of a fever within a minute. The last two minutes of the usual 3-minute temperature-taking result in a difference, say, of 101.1 degrees compared to 101.3.
Most pediatricians recommend that parents consult them if a child is running a fever of 101 degrees or more. In the case of infants under the age of 2 months, parents should consult a doctor if a fever registers 100 degrees or more.
Parents should also remember the height of the fever itself will not identify their child's illness.
"There are parents out there who are just checking their kids' temperatures all the time when they should be checking other things, too," says Barnaby Starr, a pediatrician at Union Memorial Hospital.
"A pediatrician is far more worried if a child is looking pale and sluggish, not behaving appropriately or having difficulty breathing, than if a child has a temperature of 104 and is behaving and drinking just fine."