A Cross-Sectional Study on Reference Ranges of Normal Oral Temperatures Among Students in Singapore

Abstract

Introduction: During the 2003 Severe Acute Respiratory Syndrome (SARS) outbreak, all schools in Singapore implemented twice-daily temperature monitoring for students to curtail the spread of the disease. Students were not allowed to attend school if their temperature readings were >37.8oC for students ≤12 years old, or ≥37.5oC for students >12 years old. These values had been arbitrarily determined with professional inputs. The aim of this study is to determine the reference ranges of normal oral temperatures of students in Singapore and recommend the cut-off values for febrile patients. This may be used in another similar outbreak of an infectious disease with fever. Materials and Methods: Four co-ed primary schools and 4 co-ed secondary schools were selected for this study. Four thousand and two hundred primary 1 to secondary 3 students responded (96.8%) and participated in this cross-sectional study. The mean ages of the students in the lowest (primary 1) and highest educational levels (secondary 3) were 7.4 years old and 15.3 years old, respectively. Twelve oral temperature readings per student (i.e. measurements taken 4 times a day in 3 consecutive days) were collected. Forty-six thousand seven hundred and eighty-three (92.8%) out of 50,400 temperature readings were used for the analysis as missing data were excluded. A quantile regression model was applied to estimate reference ranges of normal oral temperatures for students with adjustment for potential confounding factors. Results: The age-specific reference ranges of normal oral temperature from this study for students ≤12 years old and >12 years old were 35.7oC to 37.7oC and 35.6oC to 37.4oC, respectively. Temperatures of 37.8oC and 37.5oC are therefore recommended as the oral temperature cut-offs for those ≤12 years old and >12 years old, respectively. Conclusion: This study has provided empirical data on normal oral temperature cut-offs which could be used during temperature screening in schools. Key words: Cut-offs, Infectious diseases, SARS