1. What is an elevated body temperature (EBT)?
An adult’s body temperature will typically range between 97.5 to
97.9 degrees Fahrenheit and vary throughout the day, though 99°F is
still considered normal. Temperatures measuring higher than 100.4°F
are considered an elevated body temperature or a fever.
2. Can EBT only be detected with a thermometer?
Thermometers accurately measure body temperature, but there are also
non-contact screening tools, such as telethermographic systems,
available to identify the surface temperature of skin.
Telethermographic systems are also known as thermal imaging systems
or thermal imaging cameras. They can serve as effective tools during
initial temperature-screening assessments.
3. Does an EBT mean the screened individual has a
If an elevated body temperature is detected using a thermal imaging
device, the person’s temperature will need to be taken with a
clinical thermometer to verify they do have a fever.
4. How does thermal imaging detect an elevated skin
Thermal imaging systems
come with an infrared thermal camera and may have a temperature
reference source. The cameras detect infrared radiation on the skin
using sensors, compare it to a control group of temperatures, and
convert it to a temperature reading. They also provide an image of
body heat patterns on the skin.
5. What role does an elevated skin temperature have
in identifying those with COVID-19?
Coronavirus Disease 2019 (COVID-19) has highlighted the need for
accurate temperature screenings, especially within high-traffic
settings, such as businesses, factories, and grocery stores.
Screening for an elevated skin temperature is an initial defense
against potential health risks, including COVID-19. Fever is a
common symptom of COVID-19, usually appearing 2-14 days after
exposure to the virus. However, it’s important to remember:
- A fever does not necessarily indicate COVID-19.
A person with COVID-19 may not have symptoms or an elevated body
When thermal imaging detects elevated body temperatures, these
reading should be verified through additional methods, such as by
using a non-contact or contact thermometer.
6. Are there limitations to using thermal imaging
systems in certain locations?
Yes. The systems are designed to screen people individually rather
than in groups and to be used for initial assessment. The cameras
should not be used for evaluating the temperatures of numerous
people in crowds, which may be referred to as a “mass screening.” In
critical environments such as nursing homes, other assessment tools
may be more useful, since an incorrect measurement could result in
residents being exposed to infection.
7. Do thermal imaging systems measure skin
Scientific studies have demonstrated that when used correctly,
thermal imaging systems generally measure surface skin temperature
accurately, which is then used to estimate body temperature. The
devices can be an option during this pandemic if more traditional
temperature assessment products are unavailable due to high demand.
System accuracy depends on proper use, as well as properly preparing
an individual to be screened for the process.
8. Does the FDA have a policy on the use of thermal
imaging systems for body temperature screenings?
During the COVID-19 public health emergency, the U.S. Food and Drug
Administration (FDA) is providing regulatory flexibility on the use
of some telethermographic systems. The agency has issued guidance in
order to help increase the availability of thermal imaging for
initial body temperature measurements. This guidance relates to
triage use during the current public health emergency, and the
policy will be in place until the emergency ends. The policy applies
to all thermal imaging systems that are intended for medical or
temperature-screening purposes during the pandemic. It also outlines
recommendations regarding system performance and labeling.
9. What types of device usage does the FDA policy
The policy applies to devices that are used for initial temperature
assessment and the triage of individuals for elevated temperatures
in medical and non-medical environments. The FDA recommends that
thermal imaging not be used to simultaneously measure the
temperatures of people in crowded areas. The systems can serve as
one method for initial temperature assessment in settings such as
airports, corporate offices, factories, and stores. In other words,
they can be a first step in an overall risk management process. In
medical settings, a system could also be used to assess temperatures
and determine the need for patient isolation until further
10. Does the thermal imaging system have to be
built for medical use?
There are products from leaders in temperature measurement that
detect infrared radiation and convert these measurements into a body
temperature measurement. Some camera manufacturers, such as FLIR,
have registered products with the FDA for EBT screening purposes.
Normally, telethermographic devices that are regulated by the FDA
are used for an intended medical purpose by health care
professionals – and are labeled in this way. Telethermographic
systems that meet the definition of a device under section 201 of
the FD&C Act are regulated by the agency. However, with the
pandemic, other devices which were not specifically built for
medical purposes, may still be used for screenings due to the
shortage of temperature-measurement devices.
11. What labeling should I look for on thermal
imaging product to use it in a triage situation during COVID-19?
The FDA recommends that the device be labeled for medical use or for
body temperature measurement for diagnostic purposes, including in
non-medical environments. Each device should come with clear product
labeling and performance information. The FDA also advises that
thermal imaging equipment used in screenings may be tested and
labeled according to the IEC 80601-2-59:2017 standard for medical
electrical equipment. However, the agency is currently providing
alternatives to this testing requirement, such as if the system
meets criteria that includes:
A laboratory temperature accuracy, including the measurement
uncertainty, which is equal to or less than ±0.5°C over the
temperature range of at least 34 to 39°C.
- An accurate blackbody temperature reference source.
Stability and drift of less than 0.2°C within a
manufacturer-specified time period.
A device risk assessment that identifies potential safety issues.
12. Do thermal imaging devices need regular
Regular calibrations will be critical to ensuring your thermal
camera or thermal imaging device is operating to the manufacturer’s
accredited calibration lab
can calibrate your devices according to stringent quality processes.
At Transcat, we can ensure that each thermal imaging device meets or
continues to adhere to its regulatory standard – or to the specific
performance requirements recommended by the FDA for its screening
purposes during the pandemic.
Transcat has become the industry leader in the accredited
calibrations of test and measurement instruments. We regularly
provide services for FLIR, Seek, Fluke, AEMC, CorDEX, Testo, and
other brands of thermal imaging equipment.
13. How will I know when to calibrate my thermal
You should be able to get device performance specifications from the
manufacturer – as well as information on the recommended calibration
frequency. In many cases, this information will be included on the
product labeling as part of FDA recommendations. Transcat can
calibrate both handheld and fixed mount thermal cameras, using each
manufacturer’s established methods.
14. What’s the advantage to these systems compared
to oral thermometers during a rapid screening?
Non-contact infrared thermometers or oral thermometers require
screeners to be close to the individual receiving a temperature
check. But with thermal imaging, operators can remain at a safe
distance during quick, initial assessments. The thermal imaging
process may also be able to measure surface skin temperature faster
than the typical forehead or oral thermometer. Following EBT
detection by a thermal device, the person’s temperature can be
verified using a digital or basal thermometer.
15. What should I consider when using a thermal
camera to identify EBT?
When using a thermal imaging unit or camera, make sure:
The device is capable of screening for elevated skin temperature.
- The equipment was set up according to instructions.
Proper testing of the equipment has been done, and the correct
distance range is being used between the screener and the person
being assessed. These distances will be determined by the camera
Screeners have received training in the equipment and screening
16. What factors can affect accurate thermal
Environment, humidity, drafts, reflective backgrounds, and lighting
intensity are some of the factors that affect the accuracy of
thermal imaging results. It’s important to review any manufacturer’s
recommendations on equipment use.
Both thermal imaging systems and NCITs can measure surface
temperatures without contact. However, an NCIT is used to measure
surface temperature in one location, while a thermal imaging system
measures temperature differences across multiple skin locations,
resulting in a visual heat map with a reported body temperature on
the thermal image.
18. How do I choose a thermal imaging camera for
elevated body temperature screenings?
You will want an accurate product that allows you maintain a safe
social distance. It should meet the current FDA guidelines for
initial body temperature assessment. You will need a fast
thermography device if it’s being used in a rapid screening
The camera should be calibrated for skin temperature measurement.
- The thermal imaging tool should detect heat efficiently.
- Equipment results should be easy to read.
19. Do some systems require a calibrated blackbody?
Yes. A calibrated blackbody is a tool that checks the calibration of
an infrared temperature sensor. Your manufacturer will let you know
is needed with your device. If it is, during evaluations the
displayed image area should include the evaluated person’s entire
face and the calibrated blackbody background.
20. How can Transcat serve as a resource for my
organization’s EBT screening efforts?
Transcat offers a broad selection of thermal imaging cameras and
systems as well as NCITs. We also provide high-quality calibration
services for IR thermometers and thermal imaging devices. Our labs
are accredited to ISO/IEC 17025 requirements and ready to provide
rapid turnarounds during this time. Regular calibration will ensure
that your equipment is measuring accurately and serving as a vital
tool in identifying
elevated body temperatures. We will work to support your initial EBT screening efforts to
help you reduce infection risks.