Scientific Data Validating CORE's Accuracy

Since we released CORE, we have welcomed a lot of questions from sporting coaches to understand the strengths of the CORE Body Temperature Monitoring sensor and how it can best be used. In an earlier blog post on Data Collection and Accuracy, we outlined some of these details and would like to complement this with further information on the accuracy and validation.

CORE works. It is accurate and like any sporting equipment or tech, it is an advantage to know how it works and how the accuracy is validated so that it can be used appropriately and successfully.

Core body temperature monitoring solutions in context

To understand the CORE product better, it is useful to have some context about existing solutions for core body temperature monitoring. Up until now, the various core body temperature monitoring solutions came with hurdles; they were invasive, or they were not accurate, or they were non-continuous.

Non-continous thermometers that take single 'spot-measurements' (from the skin or inside the body) can provide results with significant deviation. With these thermometers there are more limitation for capturing consistent test results are monitoring is usually not feasible (practical) for more than a few minutes.

The most familiar core body temperature solutions that can provide continuous monitoring are ingested electronic pills (e-pills) and probes.
Electronic pills (e-pills) are small capsules that contain a battery and electronics this swallowed to monitor the temperature inside your body.

These e-pills are considered accurate and while they are continuous, the monitoring is limited to the time that the pill takes to pass through and exit the body. The recorded temperature varies as it passes through the body
because your body’s temperature is not homogeneous. This means that an acceptable tolerance is defined for e-pills and different brands of e-pills can deliver varying results.

The single-use e-pills cost between 50 - 80 Euro each and also require additional reusable hardware (activator and reader which cost 1,000-2,000€). Electronic pills are used extensively by researchers and for selective testing by coaches and elite athletes.

The alternative is the internal probe, i.e. rectal or esophagus thermometer. Rectal probes are typically utilised for medical applications although the results can still deviate from the 'Gold Standard' pulmonary artery catheter, a method which requires surgical access (meaning it is not feasible beyond medical field).

For rectal probes, there can be variations in the readings based on how a test is conducted. Some rectal thermometers take a single temperature reading while others can capture continuous readings.

For sports training, rectal probes are quite invasive for athletes so the use of this often limited to trained professionals seeking to capture medically accurate data for selective testing and studies. Further information about the measurement approach is available here.

When medical attention is required in sports, rectal thermometer are used. Trained medical staff can quickly use these with patients suffering heat-stroke and related symptoms to quickly evaluate and monitor their condition to take appropriate life-saving or risk reduction steps.

All core body temperature measurement devices have advantages and drawbacks, for example e-pills can be influenced by drinking water and rectal temperatures can be influenced by utilization of the gluteus muscles causing temperature spikes. More information on measurement systems can be found here.

The CORE Alternative

CORE Body Temperature Monitoring Technology is an alternative that is both continuous and non-invasive. It measures the core body temperature using a miniaturised energy transfer sensor that capture the thermal energy from the body. The AI algorithm crunches this data to deliver a real-time core body temperature calculation. 

But is it as accurate as the e-pill and internal probe? CORE uses both of these methods to build our algorithm (machine learning) and to validate CORE for special activities and scenarios. This also means that our continuous testing and data collection is used to continually optimise the algorithm and results.

We conduction clinical, lab and field tests to gather data and validate CORE so can show that CORE provides medical grade accuracy. In comparison, provides a high level of accuracy within the tolerance of e-pills for the activities and scenarios that CORE is validated.

Validating CORE with e-pills in different sports scenarios

We extensively and continuously test CORE with a rigid protocol involving professional athletes, regular sports people and clinical studies. We asked them to wear CORE while training and competing both indoors and outdoors, monitoring their core body temperature before, during, and after the workout. Simultaneously the athletes use a comparison thermometer.

Predominantly e-pills (BodyCap) are used as e-pills are usually more appropriate for sports, however we also use rectal probes and other methods to obtain data to validate the accuracy. With comparison (control) thermometers, it is crucial that they are calibrated and that the strict testing protocol is applied to minimise testing errors.

As a result, for the activities and scenarios against which it is validated, the CORE Body Temperature Monitoring technology has the same level of accuracy as invasive thermometers. The following charts show example for the 'everyday living' activity and endurance sports activity.

Validating CORE for medical purposes

CORE is not a medical device. However, for many years we have been working with partners conducting controlled clinical studies and trials for medical purposes. The ability to employ a non-invasive but accurate thermometer that provides real-time core body temperature data is extremely attractive within the medical profession.

These ongoing trials and studies help to improve the accuracy and validation for medical use on our path to gain formal medical approval. Currently CORE has approval under the emergency use provisionthat allow it to be sold as a clinical medical thermometer in North America.

For medical testing with CORE, the measurements are conducted by qualified healthcare professionals and the data is compared with other thermometer methods for data validation. The following charts show results from recent studies.

CORE can monitor fever in real time with a high level of accuracy. At the data of publication, CORE has a Mean Absolute Deviation of 0.21°C, which is similar to the accuracy of the e-pill.

Continuing Validation

As a new technology, we have made excellent gains improving accuracy and following many years for research and development been able to build a wearable sensor that can deliver continuous and accurate core body temperature data in real-time.

It is a continuing journey and we are continually gathering data to test and validate CORE for different conditions and scenarios. We recognise that there are scenarios where further improvement is need and have received a lot of interest from people and organisations who want to use the CORE Body Temperature Monitoring sensor for new situations and environments.

We have numerous pilot programs running and this helps us to advance our technology. The results feed our algorithm so that we can continue to provide CORE customers with updates and improvements.

If you have specific tests or requirements for monitoring core body temperature, please contact us and we can help guide you on the suitability of CORE for your specific needs.