CDE Monitoring Techniques 2 — Questions and Answers
Question 1: Which factor most commonly causes falsely LOW blood glucose readings on a home glucometer?
- Hyperlipidemia
- Severe dehydration
- Hematocrit below 25% (anemia) (Correct answer)
- Altitude above 10,000 feet
Correct answer: Hematocrit below 25% (anemia)
Low hematocrit (anemia) causes falsely low glucometer readings because less glucose-containing plasma is sampled relative to the total blood volume.
Question 2: A patient's CGM sensor glucose reads 180 mg/dL but a fingerstick capillary glucose reads 145 mg/dL. Which value should guide an insulin dosing decision?
- The CGM value, as it is more current
- The fingerstick value, as capillary blood is the reference standard (Correct answer)
- Average the two values
- Repeat the CGM calibration and wait 15 minutes
Correct answer: The fingerstick value, as capillary blood is the reference standard
When CGM and fingerstick values disagree, the capillary fingerstick is the reference standard and should guide treatment decisions.
Question 3: What is the primary clinical advantage of flash glucose monitoring (FreeStyle Libre) compared to traditional SMBG?
- It requires no sensor warm-up period
- It provides trend arrows and eliminates the need for routine fingersticks (Correct answer)
- It delivers real-time alarms for hypoglycemia
- It measures ketones simultaneously
Correct answer: It provides trend arrows and eliminates the need for routine fingersticks
Flash glucose monitoring provides trend arrows and glucose history with a scan, reducing the need for routine fingersticks while showing glucose direction.
Question 4: A patient checks fasting glucose every morning but never checks postprandial levels. What important information is she missing about her glycemic control?
- Overnight basal insulin effectiveness only
- Postprandial glucose excursions that significantly contribute to HbA1c (Correct answer)
- The effect of exercise on glucose levels
- Nocturnal hypoglycemia patterns
Correct answer: Postprandial glucose excursions that significantly contribute to HbA1c
Postprandial glucose spikes contribute significantly to overall HbA1c and are missed if only fasting readings are obtained.
Question 5: Which urine ketone result warrants immediate medical evaluation in a person with type 1 diabetes?
- Trace ketones with normal blood glucose
- Small ketones after prolonged fasting
- Moderate to large ketones regardless of blood glucose (Correct answer)
- Trace ketones after intense exercise
Correct answer: Moderate to large ketones regardless of blood glucose
Moderate to large urine ketones indicate significant ketone production and risk for diabetic ketoacidosis requiring prompt medical assessment.
Question 6: What does a CGM 'time in range' (TIR) goal of >70% specifically refer to?
- Time with glucose between 70–180 mg/dL (Correct answer)
- Time with glucose between 80–160 mg/dL
- Time with HbA1c below 7%
- Time with postprandial glucose below 200 mg/dL
Correct answer: Time with glucose between 70–180 mg/dL
International consensus defines TIR as the percentage of time glucose readings fall between 70–180 mg/dL, with >70% as the standard target.
Question 7: When should a patient with type 1 diabetes check blood glucose before driving?
- Only if they feel symptomatic hypoglycemia
- Always, and should not drive if glucose is below 90 mg/dL (Correct answer)
- Only on long trips exceeding 2 hours
- Only if their last reading was more than 4 hours ago
Correct answer: Always, and should not drive if glucose is below 90 mg/dL
Patients with type 1 diabetes should check glucose before driving and avoid driving if glucose is below 90 mg/dL to prevent hypoglycemia-related accidents.
CDE Monitoring Techniques 2
Which factor most commonly causes falsely LOW blood glucose readings on a home glucometer?