Study Questions Efficacy of Popular Forehead Thermometer

Company officials say findings skewed by improper use of product.

By Jeffrey Perkel
HealthDay Reporter
Friday, July 13, 2007; 12:00 AM

Copyright © 2007 ScoutNews, LLC. All rights reserved.

FRIDAY, July 13 (HealthDay News) -- A new study is calling into question a widely used, noninvasive method of taking an individual's temperature, but company officials claim the findings were skewed by improper use of the product.

Craig Crandall, a research scientist at the Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas, and his colleagues used a body suit filled with hot water to induce heat stress in 16 individuals, 11 of whom were female. They then measured each subject's temperature using both a temporal thermometer made by Exergen Corp., of Watertown, Mass., and an "ingestible pill telemetry system."

A temporal thermometer computes the core body temperature based on forehead temperature, as measured with an infrared scanner. An ingestible pill telemetry system uses a pill-sized device that is swallowed and transmits, from inside the body, a radio signal that correlates to core body temperature.

Crandall's team found that forehead readings were unreliable indicators of core body temperature. Though the two devices reported the same temperature at the start of the experiment, as the subjects' core body temperature (as measured by the ingestible pill) rose, the temporal thermometer readings actually fell. At 50 minutes, for instance, the internally measured temperature had risen about 0.7 degrees C, on average, while the temporal thermometer reported a decrease of about 0.3 degrees C.

The study is published in the July issue of Medicine & Science in Sports & Exercise.

The temporal thermometer "is no better" than the tried-and-true parental method of feeling a child's forehead, concluded Crandall. In fact, "putting your hand on the forehead, in my opinion, is better, because we know the subject is hot, whereas this device actually said a patient was cooling down. So, the hand could actually be more accurate."

However, Exergen President Dr. Francesco Pompei claims the researchers failed to use the product as intended, and that colored the final results.