What are some good continuous glucose monitors (CGMs) that I can order?

Recommended CGM Devices for Ordering

Based on the most recent 2025 ADA guidelines, you should order FDA-approved integrated CGM (iCGM) devices, specifically: Dexcom G6, Dexcom G7, FreeStyle Libre 2 Plus, or Eversense E3, as these are the only devices FDA-approved for integration with automated insulin delivery systems and meet the highest accuracy standards. 1

Device Selection Algorithm

First-Line Options (FDA iCGM-Approved):

Real-Time CGM (rtCGM) devices:

• Dexcom G7 - Most recent generation, no calibration required, nonadjunctive (no fingerstick confirmation needed for insulin dosing)
• Dexcom G6 - Proven track record, no calibration required, nonadjunctive
• Eversense E3 - Implantable option, FDA-approved for AID systems

Intermittently Scanned CGM (isCGM):

• FreeStyle Libre 2 Plus - Requires scanning at minimum every 8 hours, factory calibrated, FDA-approved for AID systems 1

Key Distinguishing Features:

Choose rtCGM (Dexcom G6/G7 or Eversense E3) when:

• Patient is on insulin therapy (especially multiple daily injections or pump)
• Real-time alerts for hypoglycemia/hyperglycemia are critical
• Patient wants continuous automatic data transmission without scanning
• Integration with automated insulin delivery systems is planned 1

Choose isCGM (FreeStyle Libre 2 Plus) when:

• Patient prefers scanning over continuous alerts
• Cost is a significant barrier (generally less expensive)
• Patient is on basal insulin only or non-insulin therapies
• Patient can commit to scanning at least every 8 hours 1

Critical Clinical Considerations

Accuracy Standards Matter:

The FDA iCGM designation represents a higher performance standard than non-iCGM devices. Only order devices with published accuracy data and FDA iCGM clearance - these are nonadjunctive, meaning patients can make insulin dosing decisions without fingerstick confirmation 2. Non-iCGM devices available internationally may require adjunctive fingerstick testing and lack robust accuracy validation 2.

Usage Requirements for Optimal Benefit:

• rtCGM devices must be worn as close to daily as possible for maximal benefit
• isCGM devices require scanning at minimum every 8 hours to avoid data gaps
• Ensure uninterrupted supply access to prevent gaps in monitoring 1

Patient Education Essentials:

• Assess for skin reactions (irritation or allergy) at follow-up visits, as these are common barriers to continued use 1
• Educate patients on interfering substances and factors affecting accuracy (temperature, humidity, altitude) 1
• Most current devices do not require user calibration, but verify device-specific requirements 1

Evidence Quality Note:

The 2025 ADA Standards of Care 1 provide the most authoritative guidance, explicitly naming these four devices as FDA-approved for the highest level of integration. While comparative reviews 3, 4 mention Medtronic Guardian as a competitor, it is notably absent from the ADA's list of FDA-approved iCGM devices for AID systems, making it a less preferred option for ordering.

Common Pitfall to Avoid:

Do not order non-FDA-approved CGM devices available internationally or online, even if less expensive. These lack the accuracy validation and nonadjunctive designation critical for safe insulin dosing decisions 2. The upfront cost savings are negated by increased risk of inaccurate readings, particularly in hypoglycemia detection where current devices still show limitations 5.