A widespread issue with potentially life-threatening consequences is impacting diabetes patients who use Abbott’s Freestyle Libre 3 and 3 plus glucose monitoring sensors. Reports of inaccurate, and dangerously low, blood sugar readings have surfaced in Switzerland and beyond, with the company confirming approximately 3 million devices in the U.S.are affected as well. The situation has raised concerns about communication from abbott to healthcare providers and patients regarding the recall and potential risks.
One of the faulty sensors from manufacturer Abbott.Image: zvg
A widespread issue is affecting numerous diabetes patients in Switzerland, with one individual criticizing the company’s communication and warning of potentially life-threatening consequences.
November 29, 2025, 11:01 PMNovember 29, 2025, 11:01 PM
Pascal Michel / ch media
Stefan Müller (name known to the editorial staff) received alarming news on Monday: his glucose monitoring device may be displaying inaccurate, and potentially dangerously low, readings. The device, a Freestyle Libre 3 and Libre 3 plus model from U.S. pharmaceutical company Abbott, is a patch-like sensor that transmits blood sugar levels to a mobile phone.
Following Abbott’s instructions, Müller checked the serial numbers of his sensors. The result was concerning: his current sensor was reporting values that were too low. Further investigation revealed that all six of his replacement sensors were also defective. “This can be fatal for diabetics,” Müller said. Inaccurate readings could lead patients to consume too many carbohydrates to avoid perceived hypoglycemia, or to delay necessary insulin injections. “A falsely measured blood sugar level can lead to blindness, leg amputation, or coma in the long term,” he explained.
The potential consequences extend far beyond Müller’s case. Abbott issued the warning after receiving 736 reports worldwide of serious incidents related to the sensor, with a suspected link to seven deaths. Approximately 3 million sensors in the United States are affected, and Swissmedic, the Swiss agency for therapeutic products, estimates that several hundred thousand devices are impacted in Switzerland.
“This Could Be Dangerous”
Alarmed by the situation, Müller immediately contacted Abbott requesting a replacement sensor. When he didn’t receive a confirmation email, he called the company’s hotline, only to be told that a replacement wouldn’t be available for five days, and expedited shipping wasn’t an option.
Müller was unwilling to wait five days for a functioning sensor. “This could be dangerous.” He contacted his family doctor, who was unaware of the issue. He then reached out to a local pharmacy, which also had no information. The pharmacy subsequently tested its own sensors and found two that were working. “I was able to purchase a working sensor,” Müller said, noting that each sensor costs 89 Swiss francs, with the majority covered by health insurance.
Müller described the company’s communication as “unprofessional.” “In a situation like this, doctors and pharmacists shouldn’t be in the dark.” He also believes a public warning from the authorities was necessary. “There are people who don’t check their email every day. They may currently have extremely high blood sugar levels and could potentially fall into a coma.”
Abbott Says It Acted Quickly
In a message to customers on Monday, Abbott stated that it had informed Swissmedic about the faulty sensors. An Abbott spokesperson confirmed this to “Schweiz am Wochenende,” adding that the company had also contacted doctors and retailers in Switzerland.
Swissmedic confirmed receiving the notification. According to Swissmedic’s database, Abbott sent the communication on Monday, warning of “serious health risks, including possible injury or death.”
When a medical product is defective, the manufacturer must implement a “safety corrective action.” Swissmedic oversees this process. The agency doesn’t always issue its own public warnings. Notably, Swissmedic did issue a public warning on Thursday regarding plastic abrasion in the pain reliever Algifor, a situation that is not considered life-threatening.
The agency explained the difference by stating that manufacturers are responsible for informing the public about medical devices. Abbott has direct contact information for its customers. The situation is different with a drug like Algifor, where customers need to be informed through the media and the Swissmedic website.
Swissmedic explained that the fact Stefan Müller was better informed than doctors and pharmacists is due to the manufacturer’s communication strategy. The company decides who to inform first, and the order can be influenced by “the large number of affected users, as well as the volume in the market and the communication channels.” Therefore, it’s possible that end-users were notified before distributors.
German Doctor Warned in April
The Illinois-based company experienced problems with the same sensors last year, when they were found to be reporting excessively high values. Furthermore, a case in Germany suggests that the current issues may have been known for some time. According to the Deutsche Apothekerzeitung, a doctor warned in April that an Abbott device was displaying blood sugar levels that were far too low for a patient.
The patient had reportedly not injected insulin for three weeks and had been drinking large amounts of cola – without the displayed blood sugar level moving out of the hypoglycemic range. Subsequent testing revealed a much higher actual blood sugar level. “I honestly think this is a scandal,” the doctor told the newspaper.
Abbott advises affected patients: “If your symptoms do not match the sensor glucose value you are seeing, or you suspect your reading is inaccurate, confirm your reading with a fingerstick blood glucose test.” (aargauerzeitung.ch)
