White Paper

Exotag Inc. has developed a technology that aims to improve blood product temperature monitoring and guide more appropriate wastage based on established guidelines. Current temperature monitoring options consist of either chemical indicators or infrared thermometers, both of which fundamentally measure the surface temperature of blood products. However, studies have shown that the surface temperature poorly correlates with the true core temperature, particularly during transport.¹

Given their inability to monitor core temperature, chemical indicators and infrared thermometers may inappropriately suggest that a blood product has exceeded temperature thresholds, thus contributing to inappropriate blood product wastage. In addition, infrared thermometers only provide point measurements and thus can potentially miss significant temperature violations. To address this problem, Exotag Inc. has developed a technology that can accurately, continuously, and non-invasively monitor the true core temperature of blood products.


The Exotag™ consists of a small, disposable sensor unit that roughly resembles a standard chemical indicator, but that’s where the similarities end. Under the hood, the sensor contains an array of electronic temperature sensors that are used to measure temperature gradients emanating from the surface of the blood product. This high-resolution temperature data is sent to an onboard microprocessor, where algorithms are used to analyze the data in the context of thermodynamic heat transfer laws and thereby produce a core temperature measurement. If a core temperature violation has occurred, the device will flash red whenever it is interrogated (via a button). The entire temperature profile of the blood product can also be downloaded, if desired.

Pace of Technology

The technology is fairly sophisticated and enabled primarily by the massive reduction in the cost of microprocessors that has occurred over the past few years. Even just a few years ago, this type of monitoring would not have been commercially viable given the cost of the computational power required.

Looking to the Future

Advances in monitoring capabilities may ultimately allow the transfusion community to adopt more sophisticated wastage parameters. Current guidelines require blood products to be wasted if the temperature goes above 10 ºC during transportion for any amount of time. Current guidelines are compatible with current temperature monitoring options, which are unable to produce a longitudinal temperature profile for a blood product. However, with advances in technology, more sophisticated blood product wastage parameters could potentially be encoded directly into sensors and triggered based on 1) magnitude of temperature violation, 2) duration of temperature violation, 3) age of blood product, etc.

By doing this, we can ensure that blood products are not inappropriately wasted, while also improving the safety of the supply chain by providing continuous and accurate temperature monitoring.