Elevated Skin Temperature (EST)
vs Elevated Body Temperature (EBT)

The Trouble with EST

Most of us have had our temperature checked at the entrance to stores or medical offices or other locations where they are trying to guard against exposure to the coronavirus. A forehead thermometer is often used, or for larger numbers of people, an automated thermal imaging system is installed to scan the faces of several individuals at once.

The problem with these methods of measuring your temperature is that they often get it wrong.

  • False positives arise when someone has an elevated skin temperature (EST) but isn’t infected. That might be due to coming in from a hot day, or from exertion such as climbing stairs, or simply having a sunburn. The measuring device itself may not be accurate because of poor thermal stability, inaccurate sensing, and susceptibility to external influences such as cool or warm air drafts. False positives can easily lead to embarrassment or hard feelings, as well as wasting resources on secondary screenings.
  • False negatives are also a problem. Someone running a fever might have normal temperature skin if they just came in from a cool day, or if they were exposed to air conditioning. The measuring device can also be a source of error. In these cases, screening for a fever has failed, and infected individuals are allowed entrance.

For these reasons, the FDA (Food and Drug Administration) on April 17, 2020 issued thermographic system recommendations based on the global standard established by the IEC (International Electrotechnical Commission) and ISO (International Organization for Standards) for “Fever Screening Technology”. IEC 80601-2-59:2017 states that all methods of measuring elevated skin temperature (EST) are unreliable.

EBT is the Solution

IEC standard 80601-2-59:2017 also states that the only accurate method to measure human body temperature is at the inner canthi, which are the inner corners of the eyes, near the bridge of the nose. Elevated body temperature (EBT) reliably indicates the presence of a fever.

In addition, the FDA recommends that the measurement device or system:

1. Is tested and labeled consistent with the following standard: IEC 80601-2-59:2017: Medical electrical equipment – Part 2-59: Particular requirements for the basic safety and essential performance of screening thermographs for human febrile temperature screening


2. Is tested using alternative performance specifications that provide similar results to IEC 80601-2-59:2017. This could include:

  • The laboratory temperature accuracy of a screening telethermographic system, including the measurement uncertainty, is less than or equal to ±0.5°C (±0.9°F) over the temperature range of at least 34-39°C (93.2-102.2°F);
  • The system includes an accurate blackbody temperature reference source;
  • Both stability and drift are less than 0.2°C (0.36°F) within a timeframe specified by the manufacturer

Beware of Unproven Claims

Many manufacturers and service providers claim to measure EBT but fail to satisfy the IEC standard and FDA recommendations. While fever screening checkpoints are not medical devices, they give businesses the opportunity to show customers, employees, and visitors that you care, and are putting measures in place to address their safety. If those measures are not accurate and reliable, it undermines the confidence of the people you want to reassure.

The Jogan Thermal Checkpoint™ meets or exceeds every standard, and measures EBT quickly, accurately, and reliably. Here’s how it works.

Woman at counter taking mans temperature Thermal image of peole in a group and some with hot foreheads

Measuring elevated skin temperature (EST) is unreliable according to the FDA

Thermal image of elevated body temperature being measured at the interior canthus

Elevated body temperature (EBT) is measured at the inner canthi (inner corners of the eyes, near the bridge of the nose)