Dexcom G7

The Dexcom G7 is the anchor general-purpose continuous glucose monitor (CGM): a small, all-in-one sensor-and-transmitter you wear on the back of the upper arm that reads your glucose every few minutes and streams it to your phone, watch, or a receiver. It's the sensor most diabetes tech is built around, so for many people it's the default choice.

Accuracy. In Dexcom's pivotal adult trial the G7 had an overall MARD (mean absolute relative difference — lower is better) of 8.2% on the arm, the figure the FDA cited when calling it the most accurate CGM it had cleared.¹ In children and teens (ages 7–17) accuracy was essentially the same at 8.1%, and 9.3% in ages 2–6.² One small independent head-to-head study reported a higher G7 MARD (13.6%), a useful reminder that real-world accuracy varies by person, site, and sensor.³

Wear, warm-up & calibration. Each sensor lasts 10 days, plus a 12-hour grace window to swap it.⁴ It is factory-calibrated — no fingersticks, scanning, or calibration ever required — and warms up in about 30 minutes, the fastest of any CGM.⁵ A longer 15-day version (adults 18+) was FDA-cleared in April 2025 with an 8.0% MARD.⁶

Alerts. Beyond customizable high/low alerts, the G7 includes a predictive "Urgent Low Soon" alert that warns you roughly 20 minutes before a serious low, and it can alert on a phone, smartwatch, or optional receiver.⁴

What it works with — its biggest strength. The G7 drives the Tandem t:slim X2 (Control-IQ),⁷ the Tandem Mobi (from May 2024),⁸ Omnipod 5, and the iLet Bionic Pancreas.⁹ It is also supported by every major open-source / DIY loop — Loop, Trio/iAPS, and AndroidAPS — typically via xDrip+, Juggluco, or a patched Dexcom app, though note the G7 does less on-sensor data smoothing than the G6.¹⁰ That breadth is why it anchors so many automated insulin delivery (AID) systems and loops.

Who it's for. Anyone with diabetes ages 2 and older, and it is indicated for use during pregnancy (type 1, type 2, or gestational).⁴¹¹

Ketones. None. Like all current mainstream CGMs the G7 senses glucose only — it cannot warn you about the ketones that precede diabetic ketoacidosis (DKA). That's the category's main blind spot.

Access & cost. The G7 is sold across the US, UK, EU, Canada, Australia, and Japan, is covered by Medicare for eligible US patients, and is reimbursed by many health systems. Without coverage it's expensive — a high out-of-pocket cost at US cash prices, partly offset by Dexcom's pharmacy savings program.¹²

What's coming. The headline is the 15-day G7, rolling out through 2025 and being added to AID partners over time;⁶ beyond it, Dexcom's roadmap points toward longer wear and tighter pump integration. The sensing gap — interstitial lag and the absence of ketones — is what the next generation of CGMs must close.

References

1. Garg SK, et al. Accuracy and Safety of Dexcom G7 Continuous Glucose Monitoring in Adults with Diabetes. Diabetes Technology & Therapeutics (2022). PMID 35157505. https://doi.org/10.1089/dia.2022.0011 ↩

2. Laffel LM, et al. Accuracy of a Seventh-Generation Continuous Glucose Monitoring System in Children and Adolescents With Type 1 Diabetes. Journal of Diabetes Science and Technology (2022). PMID 35466707. https://doi.org/10.1177/19322968221091816 ↩

3. Hanson K, et al. Comparison of Point Accuracy Between Two Widely Used Continuous Glucose Monitoring Systems. Journal of Diabetes Science and Technology (2024). PMID 38189290. https://doi.org/10.1177/19322968231225676 ↩

4. DexCom, Inc. Dexcom G7 Receives FDA Clearance: The Most Accurate CGM System Cleared in the U.S. Dexcom investor relations (2022). https://investors.dexcom.com/news/news-details/2022/Dexcom-G7-Receives-FDA-Clearance-The-Most-Accurate-Continuous-Glucose-Monitoring-System-Cleared-in-the-U.S/default.aspx ↩ ↩² ↩³

5. Breakthrough T1D. Dexcom G7 Continuous Glucose Monitor Cleared by the FDA (2022). https://www.breakthrought1d.org/news-and-updates/dexcom-g7-continuous-glucose-monitor-cleared-fda/ ↩

6. Dexcom G7 15 Day Receives FDA Clearance: the Longest Lasting Wearable and Most Accurate CGM System. TechTarget (2025). https://www.techtarget.com/pharmalifesciences/news/366622327/FDA-clears-Dexcom-G7-15-Day-continuous-glucose-monitor — and the 15-day pivotal accuracy data: Garg SK, et al. Accuracy of the 15.5-Day G7 iCGM in Adults with Diabetes. Diabetes Technology & Therapeutics (2025). PMID 40108991. https://doi.org/10.1089/dia.2025.0139 ↩ ↩²

7. Dexcom. Dexcom G7 is now compatible with Tandem t:slim X2 pump. https://www.dexcom.com/en-us/all-access/dexcom-cgm-explained/g7-integrates-with-tandem ↩

8. Tandem Mobi Insulin Pump Now Compatible with Dexcom G7 CGM. Drug Delivery Business (29 May 2024). https://www.drugdeliverybusiness.com/tandem-pairs-mobi-with-dexcom-g7/ ↩

9. With Beta Bionics collab, Dexcom lines up G7 sensor's 2nd insulin pump partner. Fierce Biotech. https://www.fiercebiotech.com/medtech/beta-bionics-collab-dexcom-lines-g7-sensors-2nd-insulin-pump-partner-many-days ↩

10. AndroidAPS documentation. Dexcom G7 and ONE+. https://androidaps.readthedocs.io/en/latest/CompatibleCgms/DexcomG7.html ↩

11. Dexcom. Can Dexcom G7 CGM be worn during pregnancy? https://www.dexcom.com/en-us/faqs/can-dexcom-be-worn-during-pregnancy ↩

12. How much does Dexcom G7 cost without insurance? SingleCare. https://www.singlecare.com/blog/dexcom-g7-without-insurance/ ↩