Table 2. Associations between temperature measurements by 3 infrared thermal detection systems and potential covariates, using bivariate analysis, among patients in 3 emergency departments, 2008–2009*.

Characteristics	Oral thermometer, n = 2,873 patients	OptoTherm, n = 2,809 patients	FLIR, n = 2,314 patients	Wahl, n = 2,848 patients
Gender
Male mean temperature, °F (SD)	97.85 (0.91)	94.36 (1.25)	95.77 (1.33)	89.52 (2.40)
Female mean temperature, °F (SD)	97.95 (0.87)	94.19 (1.27)	95.59 (1.40)	89.23 (2.73)
p value (t test)	0.002	<0.001	0.002	0.003
Age
Correlation coefficient r	–0.12	–0.15	–0.10	–0.10
p value	<0.001	<0.001	<0.001	<0.001
Time of day
Correlation coefficient r	0.08	0.24	0.19	0.27
p value	<0.001	<0.001	<0.001	<0.001
Antipyretic/analgesic use
Yes (mean temperature °F) (SD)	97.96 (1.01)	94.39 (1.34)	95.76 (1.47)	89.47 (2.61)
No (mean temperature °F) (SD)	97.86 (0.81)	94.22 (1.20)	95.64 (1.32)	89.35 (2.54)
p value (t test)	0.003	<0.001	0.048	0.21
Room temperature
Correlation coefficient r	0.01	0.19	0.19	0.19
p value	0.77	<0.001	<0.001	<0.001
Oral temperature
Correlation coefficient r	–	0.43	0.42	0.14
p value	–	<0.001	<0.001	<0.001

*FLIR ThermoVision A20M (FLIR Systems Inc., Boston, MA, USA), OptoTherm Thermoscreen (OptoTherm Thermal Imaging Systems and Infrared Cameras Inc., Sewickley, PA, USA), and Wahl Fever Alert Imager HSI2000S (Wahl Instruments Inc., Asheville, NC, USA).