Ahead of Apple: Wearables to optically estimate blood sugar levels with "medical-grade" accuracy

Actxa offers a smart ring that is expected to provide an estimate of blood sugar levels in the future, although directly measuring blood glucose with noninvasive methods has proven to be very difficult. The corresponding press release has to be read pretty carefully to get a clear picture of how this feature supposedly works.

According to the manufacturer, the AI and optical sensors are used to provide insight into blood glucose levels. Therefore, "insight" does not refer to an exact measurement. Instead, a dynamic range is supposed to be displayed after a one-minute measurement. The press release does not specify how wide this dynamic range is. In principle, it is entirely acceptable to report values as a range rather than exact numbers, and in scientific contexts measurement uncertainty is always expressed in ranges. However, a blood sugar range might not be useful if the ranges are too broad.

The smart ring also claims a "medical-grade" risk evaluation of developing type 2 diabetes. This evaluation is based on values collected over 3 days. It’s unclear to what extent the PPG sensors are actually used for this. This risk might also be based on activity data. According to the manufacturer, the blood glucose estimate is not suitable for people with type 1 diabetes or hypoglycemia, so the feature is definitely not a replacement for invasive blood testing or a CGM.