CDE Technology in Diabetes 3 — Questions and Answers
Question 1: Which metric from CGM data represents the percentage of time glucose levels are between 70–180 mg/dL?
- GMI (Glucose Management Indicator)
- Time in Range (TIR) (Correct answer)
- Coefficient of Variation (CV)
- Mean Amplitude of Glycemic Excursions (MAGE)
Correct answer: Time in Range (TIR)
Time in Range (TIR) is the percentage of CGM readings within the target glucose range of 70–180 mg/dL and is a key outcome metric.
Question 2: A patient using a CGM asks whether they can use acetaminophen while wearing their sensor. Which CGM system is MOST affected by acetaminophen interference?
- Dexcom G6
- Abbott FreeStyle Libre 2
- Medtronic Enlite (older generation) (Correct answer)
- Senseonics Eversense
Correct answer: Medtronic Enlite (older generation)
Older Medtronic sensors using electrochemical detection were significantly affected by acetaminophen, which could falsely elevate readings.
Question 3: What is the primary purpose of a 'suspend on low' feature on a sensor-augmented insulin pump?
- Suspend insulin delivery when CGM glucose drops below a set threshold (Correct answer)
- Alert the patient to deliver a correction bolus
- Stop basal delivery at a set time of night
- Pause the pump when the sensor signal is lost
Correct answer: Suspend insulin delivery when CGM glucose drops below a set threshold
The 'suspend on low' feature automatically pauses insulin delivery when CGM glucose falls below a programmed threshold to prevent or reduce hypoglycemia.
Question 4: A CDE is helping a patient select a CGM insertion site. Which site is FDA-approved for ALL major CGM brands?
- Upper arm
- Abdomen (Correct answer)
- Thigh
- Calf
Correct answer: Abdomen
The abdomen (specifically the periumbilical area) is the traditional FDA-approved insertion site across all major CGM systems.
Question 5: When a patient's CGM shows a rapidly falling glucose arrow (>3 mg/dL/min), what action is most appropriate?
- Treat for hypoglycemia even if glucose is currently above 80 mg/dL (Correct answer)
- Wait until glucose reaches 70 mg/dL before treating
- Ignore the arrow if no symptoms are present
- Calibrate the sensor with a fingerstick before acting
Correct answer: Treat for hypoglycemia even if glucose is currently above 80 mg/dL
A rapid downward trend arrow indicates the glucose is falling quickly; treating preemptively when above 80 mg/dL can prevent hypoglycemia.
Question 6: What is the recommended warm-up period for the Dexcom G7 sensor before it begins providing glucose readings?
- 30 minutes
- 1 hour
- 2 hours (Correct answer)
- 12 hours
Correct answer: 2 hours
The Dexcom G7 requires a 2-hour warm-up period after insertion before it begins providing accurate continuous glucose readings.
Question 7: A type 1 patient using a closed-loop system reports frequent auto-mode exits. Which patient behavior most commonly causes this?
- Failing to enter carbohydrate counts for meals (Correct answer)
- Sleeping on top of the pump
- Exercising more than 30 minutes per day
- Using the incorrect type of infusion set
Correct answer: Failing to enter carbohydrate counts for meals
Most closed-loop systems require meal announcements (carb entries); missed bolus announcements lead to large post-meal glucose spikes that exceed auto-mode limits.
CDE Technology in Diabetes 3
Which metric from CGM data represents the percentage of time glucose levels are between 70–180 mg/dL?