When measuring core body temperature with a thermometer inside the body, like with a rectal or a sublingual thermometer, only bench testing of the temperature sensor is required showing an accuracy below 0.1 °C according to ASTM 1112 E.  

For core body temperature measured on the skin, the ISO_80601-2-56 requires both temperature sensor accuracy and clinical accuracy. The CALERA® , with a bias below 0.1°C and a limit of agreement below 0.7°C (at the chest) has a better clinical accuracy than most common medically certified ear thermometers and are also better than any skin-based continuous medical thermometers.  

To receive clinical accuracy however, a study needs to be conducted with a minimum of 105 patients, with 30 % of them showing fever, and the solution needs to be compared to a gold standard. We are happy to support our clients in pursuing a clinical validation study. 

No, our sensor can be mounted inside the housing on a printed circuit board close to the skin facing the housing. Often the sensor is integrated on the same board as a PPG sensor. The housing material can be plastic or glass.

The CALERA® solution itself is not medically certified, and cannot be since the integration of it and the use case varies. However, we support our clients of integration in the process of applying for an FDA or similar, for their finished products, if they so wish. One of our clients, Corsano, has integrated the CALERA® into their wristband which has received MedCE.

Depending on the intended use, yes. We have for example integrated our sensor in the Corsano wristband, which has received MedCE. Furthermore, since our accuracy is in the same range as a medically certified ear thermometer, it is sufficient for Ward and Home settings. 

Yes, there are independent studies on the accuracy of our solution for the wrist and chest. Furthermore, we have performed many internal studies showing the accuracy in different use cases.

Access our validation studies or please contact us for more information.

Our solution needs both a heat flux sensor and a skin temperature sensor. The heat flux sensor measures the thermal energy coming from the body, while the skin temperature sensor gives an absolute reference. The skin temperature reading is adjusted via a smart algorithm to core body temperature using heat flux. 

A skin temperature sensor only gives you skin temperature and not real core body temperature. We combine the skin temperature sensor with a heat flux sensor. Both signals are combined in a smart algorithm to result in true core body temperature. greenteg has spent 5 years of development and many clinical data collections with gold standards, resulting in clinical grade core body temperature algorithms for different body positions and use cases. 

For ovulation tracking the Basal Body Temperature (BBT), which is referring to the lowest temperature during the night, is derived from the continuous curve every night. The BBT will rise slightly, between 0.3 °C and 0.5 °C, once ovulation has happened and stays high during the second half of the cycle. Deriving the BBT from a continuous core body temperature signal is much more accurate than from a spot measurement in the morning with a sublingual thermometer, or from just skin temperature which is highly influenced by the environment. 

Sleep tracking with core body temperature is not another way of measuring sleep phases, rather it is a complementary measurement which gives more insight into recovery, jetlag and developing diseases.

The core body temperature variation over a 24-hour period is linked to the circadian rhythm of the body. The temperature is dropping by approximately 0.5 °C – 1 °C during the night. The more the temperature drops during the night, the better the body recovers. A low drop of the temperature may indicate that the body is not recovering well, which could be because of jetlag, alcohol, physical or psychological exhaustion or a disease like Alzheimer or Parkinson. 

Please visit www.corebodytemp.com to read about our CORE solution for athletes and fitness. 

The heat flux sensor consumes no energy but needs to be digitalized with an ADC. Temperature sensors energy consumption can be read from the spec sheet. The algorithm is very small and energy consumption can be neglected. Overall, the energy consumption is less than 70 μW. 

The algorithm will be delivered as a compiled library for your micro controller. The size is less than 20 kB and the memory usage less than 10kB.  

The development kit contains everything you need for testing and integrating the CALERA® solution into your wearable. It includes the integration manual, which describes how you have to design and test your hardware, how the algorithm needs to be integrated, tested, and fine-tuned, and many tips for industrialization of the solution, e.g. PCBA testing and final product testing.  

The cost is dependent on the volume and is in the same range as a chip-based IR temperature sensor for wearables.