Is the SiBionics GS1 CGM Accurate and Can I Buy It in Europe?

The SiBionics GS1 availability in Europe changes often and its accuracy story is still mostly a manufacturer claim.

Availability changes by country. Check current local sellers or the maker's site before you plan an order.

Is the SiBionics GS1 CGM accurate, and can I buy it in Europe?

Can I buy it? Availability in Europe changes often, and some countries restrict sales or imports. The situation is not the same across every country, so check current local sellers and the SiBionics site for your country before you plan an order.

Is it accurate? SiBionics says the GS1 is factory-calibrated and gives a manufacturer-reported MARD figure, often around 9%. MARD is mean absolute relative difference against a reference. The problem is not the number. It is that I cannot point you to a large independent study of the GS1. Compare that with Libre and Dexcom, where independent data exists. Accuracy claims for the GS1 stay mostly a manufacturer claim.

Why MARD is not the whole answer

A MARD around 9% sounds good, but it is an average across the whole sensor wear. It can hide the exact moments you care about: a meal spike, an overnight dip, or a fast rise after training. A sensor can look fine on average and still rank two meals the wrong way round.

MARD also treats a 20 mg/dL error differently depending on whether glucose is 100 or 200, so the relative number can feel more forgiving than the absolute error on a graph.

This is why average accuracy is not enough.

What CGM accuracy looks like in real data

A CGM does not read blood. It reads glucose in the interstitial fluid just under the skin. Blood glucose changes first, then that fluid follows by about 5 to 15 minutes. On a graph, a perfectly working CGM looks late during a fast rise. It can read lower than blood at the peak and higher as blood falls, because the fluid has not caught up.

If you wear a CGM and fingerstick at the same time, you will see scatter. The CGM line will not track every fingerstick point. That is expected, not a broken sensor. A sharp overnight dip that recovers when you roll over is usually a compression low, where pressure on the sensor reduces local fluid and the reading drops. That is a sensor artefact, not your glucose.

What should I use instead in Germany?

• Already have a Libre, Dexcom, Lingo or SiBionics sensor? Export the file and run the free report. It reads LibreView, Dexcom Clarity or Stelo, Lingo, SiBionics and Apple Health exports in the browser, no account, nothing uploaded.
• No sensor yet? Order a 30-day wellness sensor that ships to Germany. It costs $70, no membership, and the app puts the glucose curve next to meals and workouts. It is not a medical device and not for dosing insulin.

The mistake people make with CGM accuracy

The common mistake is treating accuracy as a single pass or fail number. The real question is whether the sensor gives you the same decision at the moments you care about. If a sensor reads consistently high all day, that is a bias you can adjust for. If it reads high after pasta but low after rice, that is more difficult.

See your own numbers before you over-read a product claim. Drop a LibreView, Dexcom Clarity, Stelo, Lingo or SiBionics export into the free CGM report, or if you have no sensor, order HealthOS Sensor at https://healthosx.com/glucose/sensor. It is $70 for 30 days, no membership, and it turns the accuracy question into your own meal-by-meal data.