Hands On Webinar | CGM Troubleshooting Cheat Sheets | Recording-CGM Troubleshooting Cheat Sheets

Video Transcription

Video Summary

This Diabetes Care webinar focused on practical “CGM troubleshooting cheat sheets” for clinicians and diabetes educators. Dr. Gwendolyn Jack moderated, with presentations from CDCES/RDN Heather Renoy and endocrinologist Dr. David Ahn.<br /><br />Renoy reviewed how CGMs measure glucose in interstitial fluid (not blood), creating a typical 5–10 minute lag. She emphasized that fingerstick and CGM values may differ; a common rule is that readings within ~20% are acceptable, and calibration (when supported) may be needed if discrepancies are larger. She outlined FDA-approved CGM options—Dexcom (G6, G7 10- and 15-day), Abbott Libre (2 Plus, 3 Plus), Medtronic sensors (primarily for the 780G system, plus standalone Simplera), and the implanted Eversense 365—as well as new OTC “wellness” sensors (Dexcom Stelo and Abbott Lingo), noting they lack hypo/hyper alerts and have capped display ranges. Troubleshooting tips included addressing connectivity loss (reset Bluetooth, clear old pairings, maintain proximity/line of sight), managing sleep-related signal issues, and treating adhesive irritation using off-label Flonase, barrier wipes, or barrier films.<br /><br />Ahn addressed “compression/pressure lows” (sensor-induced pressure attenuation), especially overnight, explaining these are measurement artifacts from reduced interstitial fluid flow. Strategies included changing placement, using padding/overlays, or considering implanted CGM. He also discussed early-wear inflammatory inaccuracy, sensor-to-sensor variability, manufacturing failures/recalls and how to obtain replacements, medication interferences (e.g., high-dose acetaminophen, hydroxyurea; high-dose vitamin C for Libre; tetracyclines/mannitol for Eversense), and the uncertain evidence around temperature and hydration effects. He highlighted alert fatigue and recommended individualized alert settings, including delayed high alerts and different day/night profiles. Finally, he cautioned that GMI may overestimate A1C in people without diabetes and that “glycation gaps” can cause consistent differences between lab A1C and CGM-derived estimates.

Keywords

CGM troubleshooting

continuous glucose monitoring

interstitial fluid glucose lag

fingerstick vs CGM accuracy

CGM calibration

Dexcom G6 G7

Abbott FreeStyle Libre 2 Plus 3 Plus

Medtronic 780G Simplera sensor

Eversense 365 implanted CGM

compression lows pressure attenuation

CGM alert fatigue individualized settings