Would a glucose monitor change your care? Start with the question

What does the sensor measure?

A CGM uses a small sensor under the skin to estimate glucose in the fluid between cells, called interstitial fluid. It sends readings to a receiver or compatible device so you can see changes over time. Many systems also show trend arrows or provide alerts, depending on the model.

Interstitial glucose generally tracks blood glucose, but the values may differ, especially when glucose is rising or falling quickly. The sensor is not drawing a new blood sample every few minutes. That difference matters when you are comparing a sensor reading with a finger-stick result.

Learn the instructions for the exact device you use. Sensor replacement, alerts, medication interference and the circumstances that require a finger-stick check can differ between products.

Sources: 1, 2

How is this different from an A1c or glucose test?

A laboratory glucose test measures glucose at the time the sample is collected. A1c reflects an average over roughly three months. A CGM supplies a series of estimates during the time it is worn, which may help show when glucose is higher or lower.

These tools have different jobs. The 2026 ADA diagnostic guidance says there is insufficient evidence to use CGM to screen for or diagnose prediabetes or diabetes. A concerning sensor pattern is a reason to discuss appropriate testing with a clinician.

One spike after a meal does not establish a diagnosis. A graph also cannot show whether you have plaque in your arteries or explain your cardiovascular risk by itself.

Sources: 1, 4

Understand an A1c result in the prediabetes range

Who may benefit from CGM?

The 2026 ADA recommendations support CGM in people with diabetes who use insulin, use other medicines that can cause low glucose, or have another diabetes treatment situation in which CGM helps management. The decision includes the person’s needs, preferences and ability to use the information safely.

The useful question is what the readings would change: adjusting treatment, identifying low glucose, understanding a pattern or assessing how a care plan is working. Some people use a device continuously. Others may use monitoring for a defined period with their clinical team.

Ask who will teach you to use it and who will review the data. Access to readings and support for interpreting them are both parts of the treatment plan.

Sources: 1, 2

Does being sold without a prescription mean it is right for me?

Over-the-counter availability describes how a device can be obtained. Its intended users and safety features still matter. For example, the FDA’s first OTC CGM clearance, for Stelo in 2024, covered adults 18 and older who do not use insulin, including some people without diabetes.

That clearance did not include people with problematic low glucose, because that system was not designed to alert them to potentially dangerous hypoglycemia. An OTC device should not be assumed to have the same treatment role as a prescribed system.

Before buying, check the current labeling, phone compatibility, ongoing sensor cost and how you would get help. Discuss whether the information would address a medical question you actually have.

Sources: 3

Look for a useful pattern

Agree on what you are watching before you begin. If your clinician is evaluating overnight lows, the relevant pattern differs from a short period of monitoring to review a treatment change. The target and response should fit the reason for monitoring.

Keep brief notes about medicines, meals, activity and symptoms when your care team asks for them. A few useful details can make a pattern easier to discuss than an isolated screenshot without context.

If a reading seems inconsistent with how you feel, follow the device instructions and your care plan about checking a blood glucose value and getting help. Do not ignore symptoms because an app looks reassuring, or change prescription doses based on a result you have not been taught to act on.

Sources: 1, 2, 3

Where does pregnancy history fit?

Bring a history of gestational diabetes into this discussion, even if you are considering a monitor years after delivery. The first question is whether you are up to date with recommended laboratory screening. Buying a sensor should not replace that conversation.

If you are pregnant or recently delivered, use the testing and monitoring plan your maternity and diabetes teams recommend. Pregnancy has its own glucose goals and clinical decisions. A target found in a general wellness app may not fit that care plan.

Sources: 2, 4, 5

Review follow-up after gestational diabetes

Decide what would make the information useful

Before starting, write down the question, the planned length of monitoring and who will interpret the results. Agree on what should prompt a call and when you will review whether the device helped.

Your Heart Story can place glucose information beside pregnancy history, medicines, blood pressure, cholesterol and symptoms. The aim is a conversation that changes something useful in care, with support if the data become confusing or burdensome.

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