Blood Sugar Readings from Smart Watches and Smart Rings are Unreliable

On February 21st, 2024, the FDA issued a new warning to the public regarding the use of smartwatches and smart rings for noninvasive blood sugar readings. Because this technology doesn't pierce the skin, the readings are unreliable. Non-invasive technologies, like smartwatches and rings, attempt to estimate glucose levels through indirect means like sweat or skin measurement. These methods struggle with consistency and accuracy because sweat or skin do not reflect blood glucose levels as accurately.

This poses a risk to diabetics using insulin. An inaccurate dose based on unreliable readings can lead to severe low blood sugar levels, potentially requiring assistance.

Accurate blood sugar readings require piercing the skin because they rely on direct access to blood or interstitial fluid, which contains glucose levels. Blood glucose levels are the most accurate measure of sugar in the body because the bloodstream directly reflects the glucose levels present.

Standalone smartwatches and rings differ from FDA-approved apps that receive data from continuous glucose monitors (CGMs), which pierce the skin and transmit data to blood glucose apps.

Anyone who has encountered a problem with inaccurate blood sugar readings using these devices is encouraged to report the issue through the FDA MedWatch Voluntary Reporting Form.