Disruption by Continuous Glucose Monitoring (CGM)

Disruption by Continuous Glucose Monitoring (CGM)

Continuous glucose monitoring (CGM) has taken over most of the work test strips used to do for many people with diabetes, but it hasn't retired the meter. A CGM is a small sensor worn on the body that estimates glucose every few minutes. As of October 2026, the American Diabetes Association (ADA) says anyone using a CGM must also have access to blood glucose monitoring (BGM), meaning a meter and strips, at all times [1]. So the disruption is real, but it's a demotion: the strip went from main tool to backup.

How FDA labeling moved the meter to the back seat

The idea is older than most people expect. In 1962, Clark and Lyons published a paper on electrode systems for continuous monitoring in cardiovascular surgery [2].

The first commercial CGM took almost four decades more. In June 1999 the FDA approved the MiniMed Continuous Glucose Monitoring System, which recorded glucose in interstitial fluid (the fluid around cells just under the skin) for a clinician to download and review later [3]. Its approval said that data should "supplement, not replace" readings from a home meter [3]. The Dexcom STS, approved in March 2006, showed readings to the wearer, yet carried the same limit: it was an adjunctive device meant "to complement, not replace" standard home glucose monitoring [4].

Here's what surprised us: that limit held for 17 years. The turn came in December 2016, when the FDA approved the Dexcom G5 Mobile as "designed to replace fingerstick blood glucose testing for diabetes treatment decisions" [5]. Abbott's first FreeStyle Libre followed in September 2017 with a factory-calibrated sensor and the same replacement claim [6]. Then, in March 2018, the FDA authorized the Dexcom G6. Once the user entered the calibration code that comes with each sensor, it needed no fingerstick calibration for its 10-day life [7]. The G6 has since been replaced by Dexcom's G7 sensors, and Dexcom stopped manufacturing it after July 1, 2026 [8].

Calibration kept some strips in the routine

Calibration means entering a fingerstick reading so the sensor can correct its own estimate. It is the quiet reason strips didn't vanish the moment CGMs arrived. Even the G6 fell back on it: a user who skipped the code had to enter two fingerstick values at startup and every 24 hours after that [7].

Some current sensors still build calibration in. The Eversense 365, which a clinician implants under the skin for up to one year, asks for four fingerstick calibrations after its 24-hour warm-up, then one a day through day 13, then one a week [9]. For people on that system, a meter stays part of the weekly routine. We go deeper on that sensor in Implantable Fluorescence Sensors (Eversense).

How much strip use actually fell

The ADA puts the change plainly: CGM "removes the burden of frequent BGM" [1]. For contrast, it notes that many people on insulin who rely on a meter alone end up doing 6 to 10 fingersticks a day [1].

The best user-level numbers we found come from German insurance claims. A study of 52,296 insured people with insulin-requiring diabetes, using data from 2016 to 2021, found that nearly all CGM users cut back on test strips [10]. Among 2,306 long-term CGM users, nearly one third stopped using strips altogether. About 9% kept using them heavily, and that pattern was more common in younger people and in people with type 1 diabetes [10].

In the US, adoption has climbed fast. In a national database of electronic health records, CGM use among adults with type 1 diabetes rose from 5% in 2009 to 2011 to 57% in 2021 to 2023; among youths it went from 4% to 82% [11]. Neither study measures US test strip sales, and we didn't find a primary source that does. Our article on the impact of CGM on BGM market share looks at that question on its own.

Medicare's rules followed the labels

Coverage caught up with the technology. Medicare's glucose monitor policy, LCD L33822, once required testing with a meter four or more times a day before it would cover a CGM. A revision effective July 18, 2021 removed that requirement [12].

Strip coverage itself didn't go away. As of October 2026, the same policy covers up to 100 test strips every 3 months for people not treated with insulin and up to 300 for people who are, with more allowed when extra criteria are documented [12].

Where a meter still matters

The ADA lists the moments a CGM user needs a meter: when a reading seems wrong, while a new sensor warms up, when the sensor's signal drops out, for calibration or after a warning message, when CGM supplies are delayed, and when glucose is changing quickly [1]. Manufacturers say the same thing in their fine print. Dexcom advertises "no fingersticks," with a footnote that fingersticks are required for treatment decisions when symptoms or expectations don't match readings [13].

Abbott went as far as building the meter in. When the FDA cleared the FreeStyle Libre 2 system in June 2020, its reader included a strip port that works with FreeStyle Precision Neo test strips [14]. How often to check with a meter, and what to do with the result, is a decision for your care team. For a side-by-side look at the two methods, see CGM vs. BGM strips.

The CGM lineup in October 2026

As of October 2026, these are the prescription sensors doing most of the work strips used to do:

• Dexcom: the Dexcom G7, worn for 10 days, and the Dexcom G7 15 Day [13]. The G6 is no longer manufactured [8].
• Abbott: the FreeStyle Libre 3 Plus and FreeStyle Libre 2 Plus sensors. The original Libre 2 and Libre 3 sensors were available only through September 30, 2025 [15].
• MiniMed: the Instinct sensor, Simplera Sync, Guardian 4 and the standalone Simplera CGM [16].
• Senseonics: the implantable Eversense 365 [9].

Over-the-counter sensors now reach people who were never heavy strip users. In March 2024 the FDA cleared the Dexcom Stelo as the first over-the-counter CGM, at that time for adults who don't use insulin and don't have problematic hypoglycemia [17]. The ADA notes that OTC CGMs lack alarms and alerts and are meant for people not taking diabetes medicines that raise the risk of low glucose [1]. For people with diabetes, the rule from the start of this article holds whichever sensor they wear: the ADA says CGM users must have access to a meter at all times [1].