One researcher warns ear thermometers may not be accurate

From CNN Medical Correspondent Rhonda Rowland

ATLANTA (CNN) -- Some researchers are warning that easy-to-use instant-read ear thermometers may be misleading in gauging a fever.

Ear thermometers are the top choice in many doctors' offices and hospitals for taking patients' temperatures. But a physician for the University of Alabama at Birmingham says they are often inaccurate.

"We were taking their temperatures with these ear thermometers and finding they had fevers, and then spending money to do lab tests to find out why they had fevers -- only to discover there are problems with the thermometer," said Dr. Jack Modell.

His research also found very sick patients with high fevers showed normal temperatures with the ear thermometers.

Modell studied two different brands and found differences of up to 4 degrees from ear to ear in the same patient.

The manufacturers of the two thermometers tested said ear thermometers can produce erroneous readings if not properly used. As with other medical devices, ear thermometers require proper training and proper positioning to ensure accurate results.

Researchers say the convenience of ear thermometers make them essential for health care workers, but other at-home options exist

"If doctors and nurses can't even use these instruments properly, how would they expect somebody without training to do it," Modell said. "This instrument is so sensitive that if you hold it in the ear you may get one temperature, but if you move it less than half an inch, you get a different temperature."

He said at-home models should be used with caution and there are other thermometer options that may be more reliable and less expensive.

Another study on ear thermometers presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy last week suggests the devices may be responsible for spreading infections in hospitals.

Even though the probe has a disposable tip cover, researchers found bacteria on the devices themselves, and half had bacteria that could be resistant to antibiotics.

Still, researchers say the convenience of ear thermometers make them essential in some medical situations.