Infrared scanner may speed fever screening in hospitals

Mar 22, 2010 (CIDRAP News) – An infrared heat detection device showed some promise as a way to quickly screen incoming patients for fever when it was tested during the H1N1 influenza pandemic last fall, researchers at the University of Nebraska Medical Center (UNMC) in Omaha reported recently.

Several countries have used infrared thermal detection devices to screen travelers for fever. Because infrared scanning is quick and noninvasive, it may be useful to screen for fever in clinical settings as an infection control measure during a flu pandemic, according to Dr. Angela Hewlett and colleagues of UNMC.

They said the trial indicated that most patients with fever would be detected using the infrared device, although it yielded a number of false-positive results. Hewlett presented the findings last week at the Fifth Decennial International Conference on Healthcare-Associated Infections in Atlanta.

The UNMC team used a ThermoScreen device loaned by OptoTherm, which quickly measures infrared energy being emitted by the face, they reported in a news release.

The researchers conducted their study in the triage area of the UNMC emergency department, testing the device by comparing its readings with those from oral or rectal thermometers. The study ran from Nov 18, 2009, until Jan 9, during which 564 patients were screened.

Among the 564 patients, 70 readings of 100.0°F or higher (12.4%) were detected by the infrared device, compared with 43 such readings (7.6%) detected by oral or rectal thermometers, according to the study abstract.

The results showed that the ThermoScreen had a sensitivity of 70% and a specificity of 92%. Its positive predictive value was 43% and its negative predictive value 97%.

"While the ITDS [infrared scanner] had a high negative predictive value—correctly excluding most patients without fever—the machine also generated a high percentage of false positive results, measuring higher temperatures than routine temperature measurements," the news release notes.

The abstract says that although the sensitivity and positive predictive value of the device were low, the high negative predictive value means that "the vast majority of individuals with fever would be detected" with it.

Hewlett cautioned in the release that oral temperatures—which the team mainly relied on as the standard to test the device's effectiveness—are not always accurate, though they are the most widely used measurement in clinical settings.

"Further evaluation is needed; however, we feel that the technology may be a promising new infection control modality in the healthcare setting," Hewlett said at a press conference that preceded the Decennial meeting.

She said thermal temperature scanners are fairly expensive, with some models exceeding $20,000.

"We may consider purchasing one of these machines," she said. "Though we didn't study this specifically, if we're able to prevent one nosocomial case of flu by the use of this machine, it would be worth the cost."

Hewlett A, Strum RA, Ehlers L, et al. Evaluation of an infrared thermal detection system (ITDS) for fever recognition during the H1N1 influenza pandemic. Presented at the Fifth Decennial International Conference on Healthcare-Associated Infections, Atlanta, Mar 20, 2010 [Abstract]

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