Evaluation of an Infrared Thermal Detection System (ITDS) for Fever Recognition during the H1N1 Influenza Pandemic

Background: Infrared thermal detection systems (ITDS) have been utilized in several countries to screen for fever in travelers.  Since fever screening with an ITDS is non-invasive and screening can be performed quickly, this technology may be useful to screen for fever in clinical settings as an infection control measure during a pandemic.   

Objective: To evaluate an infrared thermal detection system for detection of fever in a clinical setting during the H1N1 pandemic, to compare the temperature measurements generated by the ITDS to routine temperature measurements, and to describe the utility and ease of use of the ITDS technology.

Methods: The study was initiated on November 18, 2009 and continued until January 9, 2010.  The ThermoScreen System (OptoTherm) was placed in the triage area in the Emergency Department (ED) at the University of Nebraska Medical Center and operated by a member of the study team.  Patients who presented to the ED for care were screened using the ThermoScreen and temperature measurements were also obtained by the triage nurses per routine ED protocols.  Patient age and gender were also documented. 

Results: A total of 564 patients were screened using the ITDS.  The patients’ ages ranged from 15 days old to 89 years-old (mean=31).  Forty-three triage temperatures of ≥100.0^oF were documented (7.6%), and 70 temperatures of ≥100.0^oF were documented using the ThermoScreen (12.4%).  Using triage temperature measurements as the standard, the sensitivity and specificity of the ThermoScreen to detect temperatures of ≥100.0^oF in all enrolled patients were 70% and 92% respectively.  The positive predictive value (PPV) of the ThermoScreen was 43% and the negative predictive value (NPV) was 97%.  In adult patients ≥18 years old (n=462) the sensitivity was 65%, the specificity was 94%, the PPV was 35% and the NPV was 98%.  In children ≤17 years old (n=102) the sensitivity was 75%, the specificity was 85%, the PPV was 56% and the NPV was 93%.  In children ages 2 and under (n=39) the sensitivity was 71%, the specificity was 84%, the PPV was 71% and the NPV was 84%.

Conclusions: This study, performed during the H1N1 pandemic, demonstrates that infrared thermal detection systems may be useful in clinical settings where mass screening of individuals becomes necessary. Although the sensitivities and positive predictive values were low, the high negative predictive values indicate that the vast majority of individuals with fever would be detected using the ITDS.  As a fully automated, easy-to-use system it has the potential to assist with triage of patients as well as to quickly screen persons entering a healthcare facility for fever.  Both of these applications may serve as necessary infection control measures to protect patients, employees and visitors in healthcare settings during a pandemic.