title: Utility of infrared thermography for screening febrile subjects.
abstract: OBJECTIVE
  To assess the utility of remote-sensing infrared thermography as a screening tool for fever.
  
  
  METHODS
  Cross-sectional study comparing body temperatures measured by remote-sensing infrared thermography (maximum for frontal, forehead, or lateral views) with core temperatures measured by aural or oral methods.
  
  
  METHODS
  Accident and Emergency Department, Queen Mary Hospital, Hong Kong.
  
  
  METHODS
  A total of 1517 patients (747 men, 770 women) with or without fever; 34 of whom entered a substudy to measure the effects of distance on recorded temperature.
  
  
  METHODS
  The proportions of subjects with fever (core temperature of 38°C or above) detected by remote-sensing infrared thermography compared with the proportion detected by conventional thermometry.
  
  
  RESULTS
  The correlations between infrared thermography temperatures and core temperature were only moderate (r=0.36-0.44), albeit statistically significant. The temperature recorded by infrared thermography was inversely proportional to the distance from the camera. There were 113 (7.4%) subjects with a core temperature of 38°C or above. The areas under the receiver operating characteristic curves for the three infrared thermography measurements were around 0.8. However, the maximum sensitivity achieved at a low cut-off temperature of 35°C was only 0.87 (for frontal and lateral infrared thermography views), resulting in 13% of febrile subjects being missed. The maximum forehead temperature in general had the poorest performance among the three infrared thermography views.
  
  
  CONCLUSIONS
  Forehead infrared thermography readings from a distance should be abandoned for fever screening. Although maximum lateral or frontal infrared thermography temperatures have reasonable correlations with core temperatures and areas under the receiver operating characteristic curves, the sensitivity-specificity combination might still not be high enough for screening febrile conditions, especially at border crossings with huge numbers of passengers.
authors.affiliation: Department of Earth Sciences, Faculty of Science, The University of Hong Kong, Pokfulam, Hong Kong, China. chanls@hku.hk
authors.forename: L S
authors.initials: LS
authors.lastname: Chan
authors.forename: Jessica L F
authors.initials: JL
authors.lastname: Lo
authors.forename: Cyrus R
authors.initials: CR
authors.lastname: Kumana
authors.forename: Bernard M Y
authors.initials: BM
authors.lastname: Cheung
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001831:Body Temperature; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D004636:Emergency Service, Hospital; D005260:Female; D005334:Fever / Q000175:diagnosis*; D006723:Hong Kong; D006801:Humans; D007259:Infrared Rays; D008297:Male; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D012016:Reference Values; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D013817:Thermography / Q000379:methods*; D055815:Young Adult
keywords: Body temperature; Fever; Infrared rays; Sensitivity and specificity; Thermography