Dexcom's continuous blood sugar monitors are designed to make it easier for patients with diabetes to get frequent readings without the finger prick system. The company's device can be worn as a patch and has a tiny sensor that is inserted under the skin.
But since Saturday, a glitch in Dexcom's technology has kept patients and parents of kids with diabetes from getting regular updates, leaving them unaware of potentially dangerous problems. And as of Monday, service was still intermittent.
Dexcom said the bug was specifically related to its Follow feature that allows for remote monitoring on Apple and Android devices as well as Dexcom's own hardware. In an email to CNBC on Monday, the company said that on Saturday morning it became aware of the issue, which could cause followers not to receive continuous glucose monitoring alerts. The service hasn't been fully restored but has seen "significant improvement" in performance, wrote Dexcom, which blamed the problem on a server malfunction.
"We are still investigating official root cause," the company said. "We did not release any updates or changes to cause this issue, further complicating our investigation. However, we have determined that a server overload occurred due to an unexpected system issue that generated a massive backlog, which our system was unable to sufficiently handle."
Dexcom said it's working with "our partners at Microsoft to address the problem," and recommended that customers follow updates on its Facebook page.
Carrie Diulus, a surgeon with type 1 diabetes who uses Dexcom's blood sugar monitor, said she didn't get notified on her app that there was an issue for 40 hours, which is a big concern given how much trust she puts in the company to help keep her safe.
"They have access to all of our cell phones," she said. "I get that tech fails happen, but they need a better system to manage this."
Type 1 diabetes affects more than 1.2 million Americans. It impairs the body's ability to produce the hormone insulin, which normally comes from the pancreas. Patients use trackers to monitor their blood sugar levels so they know what their body needs, whether it's more sugar or an insulin injection.
Dexcom, whose products cost more than what rivals charge, is known for its continuous and minimally invasive glucose monitors and for its remote tracking systems.
Chris Wilson, who has type 1 diabetes, said the Dexcom outage extended to patients who rely on the data to power systems known as an "artificial pancreas" that they've set up to automatically adjust insulin levels based on the readings.
Over the holiday weekend, many parents took to social media to describe the anxiety they experienced from the glitch that kept them from getting alerted overnight if their child's blood sugar levels dropped too low.
Mark Turner, co-host of the "Dads and Diabetes" podcast, said that after dealing with the stress all weekend, he was nervous about dropping his 11-year-old daughter off at school on Monday morning.
Turner, who's based in Austin, Texas, said he noticed a low reading after going to bed Friday night, but never was notified with an alarm.
"My heart skipped a beat, and I didn't realize why I didn't get an alert," Turner said. With Dexcom's service still spotty, his daughter will have to get multiple finger pricks in the nurse's office.
Turner said he's particularly concerned about the "lack of communication" from Dexcom. Another parent, Melinda Wedding, shared that sentiment. She said that the company needs to tell patients and parents when such a significant issue arises.
"Why wasn't there a push notification as soon as they realized they was a problem?" said Wedding, who has a teenage child with diabetes. "I get more information, more quickly when there's an outage on my Dropbox than I do for my child's blood sugar monitor."