Since the SARS epidemic in 2003, a number of different temperature measurement technologies have been evaluated for mass fever screening applications.  Following is a comparison of the four most common technologies employed for mass fever screening.

Internal body temperature is routinely measured using the following instruments:

• Electronic or conventional glass mercury thermometers for oral, axilla (under arm), and rectal measurements

• Tympanic (ear) thermometers

• Temporal (forehead) artery scanners

Studies demonstrate that the range of normal body temperature is much wider than is generally understood.  The table below shows the reported normal ranges of temperature measurements using different measurement sites and techniques for both men and women.

Oral measurement accuracy can be affected by operator skill (proper thermometer placement in the mouth), conditions such as nasal congestion (subjects breath through their mouths), and prior consumption of hot or cold foods and liquids.  Oral and ear thermometers, as shown below, are widely used in the health care field.  They can be accurate if administered properly, but are invasive, slow, and labor-intensive.

Tympanic measurement accuracy is highly dependent on operator skill (the probe must be aimed directly down the ear canal).  Studies shows that the lack of reproducibility by users who are not experts could lead to the failure to detect fever.

Advantages over Clinical Thermometers

• ThermoScreen can screen over 1000 subjects per hour, more than 10 times the screening rate using clinical thermometers.

• ThermoScreen measurements do not require contact with subjects and are conducted at a distance.

• ThermoScreen performs evaluations based on the temperatures of previously screened subjects, unlike clinical thermometers whose evaluations are based on comparisons to a fixed temperature threshold.  Studies indicate that temperature screening should be evaluated in relation to the temperature characteristics of specific subject groups.

• All subjects can be screened using a single ThermoScreen system.  Studies confirm the importance of using the same instrument when screening subject groups in order to obtain repeatable results.

• The accuracy of ThermoScreen measurements are not influenced by operator skill, unlike oral, ear, and temporal thermometers measurements.

• ThermoScreen measurements are not influenced by prior consumption of hot or cold liquids, unlike oral thermometer measurements.

• Holding the camera continuously leads to fatigue.

• Camera movement (even slight movement) leads to image blur, resulting in inaccurate measurements.

• Inconsistent screening distance between the camera and subject leads to inconsistent measurements.

• Cameras may be easily dropped and damaged.

Competing Technology Comparison Table

Note: Although oral thermometers may be used to confirm a fever identified by ThermoScreen, this table compares the capabilities of oral and ear thermometers when used in place of ThermoScreen as the initial mass fever screening tool.

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